diff --git a/BaseClasses.py b/BaseClasses.py
index 69669a33..b9b3dd1c 100644
--- a/BaseClasses.py
+++ b/BaseClasses.py
@@ -140,6 +140,8 @@ class World(object):
             set_player_attr('standardize_palettes', 'standardize')
             set_player_attr('force_fix', {'gt': False, 'sw': False, 'pod': False, 'tr': False})
 
+            set_player_attr('exp_cache', defaultdict(dict))
+
     def get_name_string_for_object(self, obj):
         return obj.name if self.players == 1 else f'{obj.name} ({self.get_player_names(obj.player)})'
 
@@ -394,6 +396,10 @@ class World(object):
     def clear_location_cache(self):
         self._cached_locations = None
 
+    def clear_exp_cache(self):
+        for p in range(1, self.players + 1):
+            self.exp_cache[p].clear()
+
     def get_unfilled_locations(self, player=None):
         return [location for location in self.get_locations() if (player is None or location.player == player) and location.item is None]
 
@@ -426,10 +432,14 @@ class World(object):
         else:
             return all((self.has_beaten_game(state, p) for p in range(1, self.players + 1)))
 
-    def can_beat_game(self, starting_state=None):
+    def can_beat_game(self, starting_state=None, log_error=False):
         if starting_state:
+            if self.has_beaten_game(starting_state):
+                return True
             state = starting_state.copy()
         else:
+            if self.has_beaten_game(self.state):
+                return True
             state = CollectionState(self)
 
         if self.has_beaten_game(state):
@@ -446,6 +456,9 @@ class World(object):
 
             if not sphere:
                 # ran out of places and did not finish yet, quit
+                if log_error:
+                    missing_locations = ", ".join([x.name for x in prog_locations])
+                    logging.getLogger('').error(f'Cannot reach the following locations: {missing_locations}')
                 return False
 
             for location in sphere:
@@ -460,17 +473,25 @@ class World(object):
 
 class CollectionState(object):
 
-    def __init__(self, parent):
-        self.prog_items = Counter()
+    def __init__(self, parent, skip_init=False):
         self.world = parent
-        self.reachable_regions = {player: dict() for player in range(1, parent.players + 1)}
-        self.blocked_connections = {player: dict() for player in range(1, parent.players + 1)}
-        self.events = []
-        self.path = {}
-        self.locations_checked = set()
-        self.stale = {player: True for player in range(1, parent.players + 1)}
-        for item in parent.precollected_items:
-            self.collect(item, True)
+        if not skip_init:
+            self.prog_items = Counter()
+            self.reachable_regions = {player: dict() for player in range(1, parent.players + 1)}
+            self.blocked_connections = {player: dict() for player in range(1, parent.players + 1)}
+            self.events = []
+            self.path = {}
+            self.locations_checked = set()
+            self.stale = {player: True for player in range(1, parent.players + 1)}
+            for item in parent.precollected_items:
+                self.collect(item, True)
+            # reached vs. opened in the counter
+            self.door_counter = {player: (Counter(), Counter()) for player in range(1, parent.players + 1)}
+            self.reached_doors = {player: set() for player in range(1, parent.players + 1)}
+            self.opened_doors = {player: set() for player in range(1, parent.players + 1)}
+            self.dungeons_to_check = {player: defaultdict(dict) for player in range(1, parent.players + 1)}
+        self.dungeon_limits = None
+        # self.trace = None
 
     def update_reachable_regions(self, player):
         self.stale[player] = False
@@ -481,68 +502,386 @@ class CollectionState(object):
         start = self.world.get_region('Menu', player)
         if not start in rrp:
             rrp[start] = CrystalBarrier.Orange
-            for exit in start.exits:
-                bc[exit] = CrystalBarrier.Orange
+            for conn in start.exits:
+                bc[conn] = CrystalBarrier.Orange
 
         queue = deque(self.blocked_connections[player].items())
 
+        self.traverse_world(queue, rrp, bc, player)
+        unresolved_events = [x for y in self.reachable_regions[player] for x in y.locations
+                             if x.event and x.item and (x.item.smallkey or x.item.bigkey or x.item.advancement)
+                             and x not in self.locations_checked and x.can_reach(self)]
+        unresolved_events = self._do_not_flood_the_keys(unresolved_events)
+        if len(unresolved_events) == 0:
+            self.check_key_doors_in_dungeons(rrp, player)
+
+    def traverse_world(self, queue, rrp, bc, player):
         # run BFS on all connections, and keep track of those blocked by missing items
-        while True:
-            try:
-                connection, crystal_state = queue.popleft()
-                new_region = connection.connected_region
-                if new_region is None or new_region in rrp and (new_region.type != RegionType.Dungeon or (rrp[new_region] & crystal_state) == crystal_state):
+        while len(queue) > 0:
+            connection, crystal_state = queue.popleft()
+            new_region = connection.connected_region
+            if not self.should_visit(new_region, rrp, crystal_state, player):
+                if not new_region or not self.dungeon_limits or self.possibly_connected_to_dungeon(new_region, player):
                     bc.pop(connection, None)
-                elif connection.can_reach(self):
-                    if new_region.type == RegionType.Dungeon:
-                        new_crystal_state = crystal_state
-                        for exit in new_region.exits:
-                            door = exit.door
-                            if door is not None and door.crystal == CrystalBarrier.Either and door.entrance.can_reach(self):
-                                new_crystal_state = CrystalBarrier.Either
-                                break
-                        if new_region in rrp:
-                            new_crystal_state |= rrp[new_region]
+            elif connection.can_reach(self):
+                bc.pop(connection, None)
+                if new_region.type == RegionType.Dungeon:
+                    new_crystal_state = crystal_state
+                    if new_region in rrp:
+                        new_crystal_state |= rrp[new_region]
 
-                        rrp[new_region] = new_crystal_state
-
-                        for exit in new_region.exits:
-                            door = exit.door
-                            if door is not None and not door.blocked:
+                    rrp[new_region] = new_crystal_state
+                    for conn in new_region.exits:
+                        door = conn.door
+                        if door is not None and not door.blocked:
+                            if self.valid_crystal(door, new_crystal_state):
                                 door_crystal_state = door.crystal if door.crystal else new_crystal_state
-                                bc[exit] = door_crystal_state
-                                queue.append((exit, door_crystal_state))
-                            elif door is None:
-                                queue.append((exit, new_crystal_state))
-                    else:
-                        new_crystal_state = CrystalBarrier.Orange
-                        rrp[new_region] = new_crystal_state
-                        bc.pop(connection, None)
-                        for exit in new_region.exits:
-                            bc[exit] = new_crystal_state
-                            queue.append((exit, new_crystal_state))
+                                bc[conn] = door_crystal_state
+                                queue.append((conn, door_crystal_state))
+                        elif door is None:
+                            # note: no door in dungeon indicates what exactly? (always traversable)?
+                            queue.append((conn, new_crystal_state))
+                else:
+                    new_crystal_state = CrystalBarrier.Orange
+                    rrp[new_region] = new_crystal_state
+                    for conn in new_region.exits:
+                        bc[conn] = new_crystal_state
+                        queue.append((conn, new_crystal_state))
 
-                    self.path[new_region] = (new_region.name, self.path.get(connection, None))
+                self.path[new_region] = (new_region.name, self.path.get(connection, None))
 
-                    # Retry connections if the new region can unblock them
-                    if new_region.name in indirect_connections:
-                        new_entrance = self.world.get_entrance(indirect_connections[new_region.name], player)
-                        if new_entrance in bc and new_entrance not in queue and new_entrance.parent_region in rrp:
-                            queue.append((new_entrance, rrp[new_entrance.parent_region]))
-            except IndexError:
-                break
+                # Retry connections if the new region can unblock them
+                if new_region.name in indirect_connections:
+                    new_entrance = self.world.get_entrance(indirect_connections[new_region.name], player)
+                    if new_entrance in bc and new_entrance.parent_region in rrp:
+                        new_crystal_state = rrp[new_entrance.parent_region]
+                        if (new_entrance, new_crystal_state) not in queue:
+                            queue.append((new_entrance, new_crystal_state))
+            # else those connections that are not accessible yet
+            if self.is_small_door(connection):
+                door = connection.door
+                dungeon_name = connection.parent_region.dungeon.name
+                key_logic = self.world.key_logic[player][dungeon_name]
+                if door.name not in self.reached_doors[player]:
+                    self.door_counter[player][0][dungeon_name] += 1
+                    self.reached_doors[player].add(door.name)
+                    if key_logic.sm_doors[door]:
+                        self.reached_doors[player].add(key_logic.sm_doors[door].name)
+                if not connection.can_reach(self):
+                    checklist_key = 'Universal' if self.world.retro[player] else dungeon_name
+                    checklist = self.dungeons_to_check[player][checklist_key]
+                    checklist[connection.name] = (connection, crystal_state)
+                elif door.name not in self.opened_doors[player]:
+                    opened_doors = self.opened_doors[player]
+                    door = connection.door
+                    if door.name not in opened_doors:
+                        self.door_counter[player][1][dungeon_name] += 1
+                        opened_doors.add(door.name)
+                        key_logic = self.world.key_logic[player][dungeon_name]
+                        if key_logic.sm_doors[door]:
+                            opened_doors.add(key_logic.sm_doors[door].name)
 
+    def should_visit(self, new_region, rrp, crystal_state, player):
+        if not new_region:
+            return False
+        if self.dungeon_limits and not self.possibly_connected_to_dungeon(new_region, player):
+            return False
+        if new_region not in rrp:
+            return True
+        if new_region.type != RegionType.Dungeon:
+            return False
+        return (rrp[new_region] & crystal_state) != crystal_state
+
+    def possibly_connected_to_dungeon(self, new_region, player):
+        if new_region.dungeon:
+            return new_region.dungeon.name in self.dungeon_limits
+        else:
+            return new_region.name in self.world.inaccessible_regions[player]
+
+    @staticmethod
+    def valid_crystal(door, new_crystal_state):
+        return (not door.crystal or door.crystal == CrystalBarrier.Either or new_crystal_state == CrystalBarrier.Either
+                or new_crystal_state == door.crystal)
+
+    def check_key_doors_in_dungeons(self, rrp, player):
+        for dungeon_name, checklist in self.dungeons_to_check[player].items():
+            if self.apply_dungeon_exploration(rrp, player, dungeon_name, checklist):
+                continue
+            init_door_candidates = self.should_explore_child_state(self, dungeon_name, player)
+            key_total = self.prog_items[(dungeon_keys[dungeon_name], player)]  # todo: universal
+            remaining_keys = key_total - self.door_counter[player][1][dungeon_name]
+            if not init_door_candidates or remaining_keys == 0:
+                continue
+            dungeon_doors = {x.name for x in self.world.key_logic[player][dungeon_name].sm_doors.keys()}
+
+            def valid_d_door(x):
+                return x in dungeon_doors
+
+            child_states = deque()
+            child_states.append(self)
+            visited_opened_doors = set()
+            visited_opened_doors.add(frozenset(self.opened_doors[player]))
+            terminal_states, common_regions, common_bc, common_doors = [], {}, {}, set()
+            while len(child_states) > 0:
+                next_child = child_states.popleft()
+                door_candidates = CollectionState.should_explore_child_state(next_child, dungeon_name, player)
+                child_checklist = next_child.dungeons_to_check[player][dungeon_name]
+                if door_candidates:
+                    for chosen_door in door_candidates:
+                        child_state = next_child.copy()
+                        child_queue = deque()
+                        child_state.door_counter[player][1][dungeon_name] += 1
+                        if isinstance(chosen_door, tuple):
+                            child_state.opened_doors[player].add(chosen_door[0])
+                            child_state.opened_doors[player].add(chosen_door[1])
+                            if chosen_door[0] in child_checklist:
+                                child_queue.append(child_checklist[chosen_door[0]])
+                            if chosen_door[1] in child_checklist:
+                                child_queue.append(child_checklist[chosen_door[1]])
+                        else:
+                            child_state.opened_doors[player].add(chosen_door)
+                            if chosen_door in child_checklist:
+                                child_queue.append(child_checklist[chosen_door])
+                        if child_state.opened_doors[player] not in visited_opened_doors:
+                            done = False
+                            while not done:
+                                rrp_ = child_state.reachable_regions[player]
+                                bc_ = child_state.blocked_connections[player]
+                                child_state.set_dungeon_limits(player, dungeon_name)
+                                child_queue.extend([(x, y) for x, y in bc_.items()
+                                                    if child_state.possibly_connected_to_dungeon(x.parent_region,
+                                                                                                 player)])
+                                child_state.traverse_world(child_queue, rrp_, bc_, player)
+                                new_events = child_state.sweep_for_events_once(player)
+                                child_state.stale[player] = False
+                                if new_events:
+                                    for conn in bc_:
+                                        if conn.parent_region.dungeon and conn.parent_region.dungeon.name == dungeon_name:
+                                            child_queue.append((conn, bc_[conn]))
+                                done = not new_events
+                            if child_state.opened_doors[player] not in visited_opened_doors:
+                                visited_opened_doors.add(frozenset(child_state.opened_doors[player]))
+                                child_states.append(child_state)
+                else:
+                    terminal_states.append(next_child)
+            common_regions, common_bc, common_doors, first = {}, {}, set(), True
+            bc = self.blocked_connections[player]
+            for term_state in terminal_states:
+                t_rrp = term_state.reachable_regions[player]
+                t_bc = term_state.blocked_connections[player]
+                if first:
+                    first = False
+                    common_regions = {x: y for x, y in t_rrp.items() if x not in rrp or y != rrp[x]}
+                    common_bc = {x: y for x, y in t_bc.items() if x not in bc}
+                    common_doors = {x for x in term_state.opened_doors[player] - self.opened_doors[player]
+                                    if valid_d_door(x)}
+                else:
+                    cm_rrp = {x: y for x, y in t_rrp.items() if x not in rrp or y != rrp[x]}
+                    common_regions = {k: self.comb_crys(v, cm_rrp[k]) for k, v in common_regions.items()
+                                      if k in cm_rrp and self.crys_agree(v, cm_rrp[k])}
+                    common_bc.update({x: y for x, y in t_bc.items() if x not in bc and x not in common_bc})
+                    common_doors &= {x for x in term_state.opened_doors[player] - self.opened_doors[player]
+                                     if valid_d_door(x)}
+
+            terminal_queue = deque()
+            for door in common_doors:
+                pair = self.find_door_pair(player, dungeon_name, door)
+                if door not in self.reached_doors[player]:
+                    self.door_counter[player][0][dungeon_name] += 1
+                    self.reached_doors[player].add(door)
+                    if pair not in self.reached_doors[player]:
+                        self.reached_doors[player].add(pair)
+                self.opened_doors[player].add(door)
+                if door in checklist:
+                    terminal_queue.append(checklist[door])
+                if pair not in self.opened_doors[player]:
+                    self.door_counter[player][1][dungeon_name] += 1
+
+            self.set_dungeon_limits(player, dungeon_name)
+            rrp_ = self.reachable_regions[player]
+            bc_ = self.blocked_connections[player]
+            for block, crystal in bc_.items():
+                if (block, crystal) not in terminal_queue and self.possibly_connected_to_dungeon(block.connected_region, player):
+                        terminal_queue.append((block, crystal))
+            self.traverse_world(terminal_queue, rrp_, bc_, player)
+            self.dungeon_limits = None
+
+            rrp = self.reachable_regions[player]
+            missing_regions = {x: y for x, y in common_regions.items() if x not in rrp}
+            paths = {}
+            for k in missing_regions:
+                rrp[k] = missing_regions[k]
+                possible_path = terminal_states[0].path[k]
+                self.path[k] = paths[k] = possible_path
+            missing_bc = {}
+            for blocked, crystal in common_bc.items():
+                if (blocked not in bc and blocked.parent_region in rrp
+                   and self.should_visit(blocked.connected_region, rrp, crystal, player)):
+                    missing_bc[blocked] = crystal
+            for k in missing_bc:
+                bc[k] = missing_bc[k]
+            self.record_dungeon_exploration(player, dungeon_name, checklist,
+                                            common_doors, missing_regions, missing_bc, paths)
+            checklist.clear()
+
+    @staticmethod
+    def comb_crys(a, b):
+        return a if a == b or a != CrystalBarrier.Either else b
+
+    @staticmethod
+    def crys_agree(a, b):
+        return a == b or a == CrystalBarrier.Either or b == CrystalBarrier.Either
+
+    def find_door_pair(self, player, dungeon_name, name):
+        for door in self.world.key_logic[player][dungeon_name].sm_doors.keys():
+            if door.name == name:
+                paired_door = self.world.key_logic[player][dungeon_name].sm_doors[door]
+                return paired_door.name if paired_door else None
+        return None
+
+    def set_dungeon_limits(self, player, dungeon_name):
+        if self.world.retro[player] and self.world.mode[player] == 'standard':
+            self.dungeon_limits = ['Hyrule Castle', 'Agahnims Tower']
+        else:
+            self.dungeon_limits = [dungeon_name]
+
+    @staticmethod
+    def should_explore_child_state(state, dungeon_name, player):
+        small_key_name = dungeon_keys[dungeon_name]
+        key_total = state.prog_items[(small_key_name, player)]
+        remaining_keys = key_total - state.door_counter[player][1][dungeon_name]
+        unopened_doors = state.door_counter[player][0][dungeon_name] - state.door_counter[player][1][dungeon_name]
+        if remaining_keys > 0 and unopened_doors > 0:
+            key_logic = state.world.key_logic[player][dungeon_name]
+            door_candidates, skip = [], set()
+            for door, paired in key_logic.sm_doors.items():
+                if door.name in state.reached_doors[player] and door.name not in state.opened_doors[player]:
+                    if door.name not in skip:
+                        if paired:
+                            door_candidates.append((door.name, paired.name))
+                            skip.add(paired.name)
+                        else:
+                            door_candidates.append(door.name)
+            return door_candidates
+        return None
+
+    @staticmethod
+    def print_rrp(rrp):
+        logger = logging.getLogger('')
+        logger.debug('RRP Checking')
+        for region, packet in rrp.items():
+            new_crystal_state, logic, path = packet
+            logger.debug(f'\nRegion: {region.name} (CS: {str(new_crystal_state)})')
+            for i in range(0, len(logic)):
+                logger.debug(f'{logic[i]}')
+                logger.debug(f'{",".join(str(x) for x in path[i])}')
 
     def copy(self):
-        ret = CollectionState(self.world)
+        ret = CollectionState(self.world, skip_init=True)
         ret.prog_items = self.prog_items.copy()
         ret.reachable_regions = {player: copy.copy(self.reachable_regions[player]) for player in range(1, self.world.players + 1)}
         ret.blocked_connections = {player: copy.copy(self.blocked_connections[player]) for player in range(1, self.world.players + 1)}
         ret.events = copy.copy(self.events)
         ret.path = copy.copy(self.path)
         ret.locations_checked = copy.copy(self.locations_checked)
+        ret.stale = {player: self.stale[player] for player in range(1, self.world.players + 1)}
+        ret.door_counter = {player: (copy.copy(self.door_counter[player][0]), copy.copy(self.door_counter[player][1]))
+                            for player in range(1, self.world.players + 1)}
+        ret.reached_doors = {player: copy.copy(self.reached_doors[player]) for player in range(1, self.world.players + 1)}
+        ret.opened_doors = {player: copy.copy(self.opened_doors[player]) for player in range(1, self.world.players + 1)}
+        ret.dungeons_to_check = {
+            player: defaultdict(dict, {name: copy.copy(checklist)
+                                       for name, checklist in self.dungeons_to_check[player].items()})
+            for player in range(1, self.world.players + 1)}
         return ret
 
+    def apply_dungeon_exploration(self, rrp, player, dungeon_name, checklist):
+        bc = self.blocked_connections[player]
+        ec = self.world.exp_cache[player]
+        prog_set = self.reduce_prog_items(player, dungeon_name)
+        exp_key = (prog_set, frozenset(checklist))
+        if dungeon_name in ec and exp_key in ec[dungeon_name]:
+            # apply
+            common_doors, missing_regions, missing_bc, paths = ec[dungeon_name][exp_key]
+            terminal_queue = deque()
+            for door in common_doors:
+                pair = self.find_door_pair(player, dungeon_name, door)
+                if door not in self.reached_doors[player]:
+                    self.door_counter[player][0][dungeon_name] += 1
+                    self.reached_doors[player].add(door)
+                    if pair not in self.reached_doors[player]:
+                        self.reached_doors[player].add(pair)
+                self.opened_doors[player].add(door)
+                if door in checklist:
+                    terminal_queue.append(checklist[door])
+                if pair not in self.opened_doors[player]:
+                    self.door_counter[player][1][dungeon_name] += 1
+
+            self.set_dungeon_limits(player, dungeon_name)
+            rrp_ = self.reachable_regions[player]
+            bc_ = self.blocked_connections[player]
+            for block, crystal in bc_.items():
+                if (block, crystal) not in terminal_queue and self.possibly_connected_to_dungeon(block.connected_region, player):
+                    terminal_queue.append((block, crystal))
+            self.traverse_world(terminal_queue, rrp_, bc_, player)
+            self.dungeon_limits = None
+
+            for k in missing_regions:
+                rrp[k] = missing_regions[k]
+            for r, path in paths.items():
+                self.path[r] = path
+            for k in missing_bc:
+                bc[k] = missing_bc[k]
+
+            return True
+        return False
+
+    def record_dungeon_exploration(self, player, dungeon_name, checklist,
+                                   common_doors, missing_regions, missing_bc, paths):
+        ec = self.world.exp_cache[player]
+        prog_set = self.reduce_prog_items(player, dungeon_name)
+        exp_key = (prog_set, frozenset(checklist))
+        ec[dungeon_name][exp_key] = (common_doors, missing_regions, missing_bc, paths)
+
+    def reduce_prog_items(self, player, dungeon_name):
+        # todo: possibly could include an analysis of dungeon items req. like Hammer, Hookshot, etc
+        # cross dungeon requirements may be necessary for keysanity - which invalidates the above
+        # todo: universal smalls where needed
+        life_count, bottle_count = 0, 0
+        reduced = Counter()
+        for item, cnt in self.prog_items.items():
+            item_name, item_player = item
+            if item_player == player and self.check_if_progressive(item_name):
+                if item_name.startswith('Bottle'):  # I think magic requirements can require multiple bottles
+                    bottle_count += cnt
+                elif item_name in ['Boss Heart Container', 'Sanctuary Heart Container', 'Piece of Heart']:
+                    if 'Container' in item_name:
+                        life_count += 1
+                    elif 'Piece of Heart' == item_name:
+                        life_count += .25
+                else:
+                    reduced[item] = cnt
+        if bottle_count > 0:
+            reduced[('Bottle', player)] = 1
+        if life_count >= 1:
+            reduced[('Heart Container', player)] = 1
+        return frozenset(reduced.items())
+
+    @staticmethod
+    def check_if_progressive(item_name):
+        return (item_name in
+                ['Bow', 'Progressive Bow', 'Progressive Bow (Alt)', 'Book of Mudora', 'Hammer', 'Hookshot',
+                 'Magic Mirror', 'Ocarina', 'Pegasus Boots', 'Power Glove', 'Cape', 'Mushroom', 'Shovel',
+                 'Lamp', 'Magic Powder', 'Moon Pearl', 'Cane of Somaria', 'Fire Rod', 'Flippers', 'Ice Rod',
+                 'Titans Mitts', 'Bombos', 'Ether', 'Quake', 'Master Sword', 'Tempered Sword', 'Fighter Sword',
+                 'Golden Sword', 'Progressive Sword', 'Progressive Glove', 'Silver Arrows', 'Green Pendant',
+                 'Blue Pendant', 'Red Pendant', 'Crystal 1', 'Crystal 2', 'Crystal 3', 'Crystal 4', 'Crystal 5',
+                 'Crystal 6', 'Crystal 7', 'Blue Boomerang', 'Red Boomerang', 'Blue Shield', 'Red Shield',
+                 'Mirror Shield', 'Progressive Shield', 'Bug Catching Net', 'Cane of Byrna',
+                 'Boss Heart Container', 'Sanctuary Heart Container', 'Piece of Heart', 'Magic Upgrade (1/2)',
+                 'Magic Upgrade (1/4)']
+            or item_name.startswith(('Bottle', 'Small Key', 'Big Key')))
+
     def can_reach(self, spot, resolution_hint=None, player=None):
         try:
             spot_type = spot.spot_type
@@ -558,6 +897,16 @@ class CollectionState(object):
 
         return spot.can_reach(self)
 
+    def sweep_for_events_once(self, player):
+        locations = self.world.get_filled_locations(player)
+        checked_locations = set([l for l in locations if l in self.locations_checked])
+        reachable_events = [location for location in locations if location.event and location.can_reach(self)]
+        reachable_events = self._do_not_flood_the_keys(reachable_events)
+        for event in reachable_events:
+            if event not in checked_locations:
+                self.events.append((event.name, event.player))
+                self.collect(event.item, True, event)
+        return len(reachable_events) > len(checked_locations)
 
     def sweep_for_events(self, key_only=False, locations=None):
         # this may need improvement
@@ -605,6 +954,13 @@ class CollectionState(object):
                     or not self.location_can_be_flooded(flood_location))
         return True
 
+    @staticmethod
+    def is_small_door(connection):
+        return connection and connection.door and connection.door.smallKey
+
+    def is_door_open(self, door_name, player):
+        return door_name in self.opened_doors[player]
+
     @staticmethod
     def location_can_be_flooded(location):
         return location.parent_region.name in ['Swamp Trench 1 Alcove', 'Swamp Trench 2 Alcove']
@@ -1484,6 +1840,7 @@ class Sector(object):
         self.entrance_sector = None
         self.destination_entrance = False
         self.equations = None
+        self.item_logic = set()
 
     def region_set(self):
         if self.r_name_set is None:
@@ -1736,9 +2093,7 @@ class Location(object):
         return self.always_allow(state, item) or (self.parent_region.can_fill(item) and self.item_rule(item) and (not check_access or self.can_reach(state)))
 
     def can_reach(self, state):
-        if self.parent_region.can_reach(state) and self.access_rule(state):
-            return True
-        return False
+        return self.parent_region.can_reach(state) and self.access_rule(state)
 
     def forced_big_key(self):
         if self.forced_item and self.forced_item.bigkey and self.player == self.forced_item.player:
@@ -1765,6 +2120,12 @@ class Location(object):
         world = self.parent_region.world if self.parent_region and self.parent_region.world else None
         return world.get_name_string_for_object(self) if world else f'{self.name} (Player {self.player})'
 
+    def __eq__(self, other):
+        return self.name == other.name and self.player == other.player
+
+    def __hash__(self):
+        return hash((self.name, self.player))
+
 
 class Item(object):
 
@@ -1808,6 +2169,15 @@ class Item(object):
     def compass(self):
         return self.type == 'Compass'
 
+    @property
+    def dungeon(self):
+        if not self.smallkey and not self.bigkey and not self.map and not self.compass:
+            return None
+        item_dungeon = self.name.split('(')[1][:-1]
+        if item_dungeon == 'Escape':
+            item_dungeon = 'Hyrule Castle'
+        return item_dungeon
+
     def __str__(self):
         return str(self.__unicode__())
 
@@ -2157,7 +2527,7 @@ class Spoiler(object):
 
             for player in range(1, self.world.players + 1):
                 if self.world.boss_shuffle[player] != 'none':
-                    bossmap = self.bosses[player] if self.world.players > 1 else self.bosses
+                    bossmap = self.bosses[str(player)] if self.world.players > 1 else self.bosses
                     outfile.write(f'\n\nBosses ({self.world.get_player_names(player)}):\n\n')
                     outfile.write('\n'.join([f'{x}: {y}' for x, y in bossmap.items() if y not in ['Agahnim', 'Agahnim 2', 'Ganon']]))
 
@@ -2200,6 +2570,22 @@ dungeon_names = [
     'Swamp Palace', 'Skull Woods', 'Thieves Town', 'Ice Palace', 'Misery Mire', 'Turtle Rock', 'Ganons Tower'
 ]
 
+dungeon_keys = {
+    'Hyrule Castle': 'Small Key (Escape)',
+    'Eastern Palace': 'Small Key (Eastern Palace)',
+    'Desert Palace': 'Small Key (Desert Palace)',
+    'Tower of Hera': 'Small Key (Tower of Hera)',
+    'Agahnims Tower': 'Small Key (Agahnims Tower)',
+    'Palace of Darkness': 'Small Key (Palace of Darkness)',
+    'Swamp Palace': 'Small Key (Swamp Palace)',
+    'Skull Woods': 'Small Key (Skull Woods)',
+    'Thieves Town': 'Small Key (Thieves Town)',
+    'Ice Palace': 'Small Key (Ice Palace)',
+    'Misery Mire': 'Small Key (Misery Mire)',
+    'Turtle Rock': 'Small Key (Turtle Rock)',
+    'Ganons Tower': 'Small Key (Ganons Tower)',
+    'Universal': 'Small Key (Universal)'
+}
 
 class PotItem(FastEnum):
     Nothing = 0x0
@@ -2350,3 +2736,10 @@ class Settings(object):
         args.enemy_health[p] = r(e_health)[(settings[7] & 0xE0) >> 5]
         args.enemy_damage[p] = r(e_dmg)[(settings[7] & 0x18) >> 3]
         args.shufflepots[p] = True if settings[7] & 0x4 else False
+
+
+@unique
+class KeyRuleType(FastEnum):
+    WorstCase = 0
+    AllowSmall = 1
+    Lock = 2
diff --git a/Bosses.py b/Bosses.py
index 253717bd..2718431e 100644
--- a/Bosses.py
+++ b/Bosses.py
@@ -176,8 +176,8 @@ def place_bosses(world, player):
 
         if world.boss_shuffle[player] == "simple":  # vanilla bosses shuffled
             bosses = placeable_bosses + ['Armos Knights', 'Lanmolas', 'Moldorm']
-        else: # all bosses present, the three duplicates chosen at random
-            bosses = all_bosses + [random.choice(placeable_bosses) for _ in range(3)]
+        else:  # all bosses present, the three duplicates chosen at random
+            bosses = all_bosses + random.sample(placeable_bosses, 3)
 
         logging.getLogger('').debug('Bosses chosen %s', bosses)
 
diff --git a/DoorShuffle.py b/DoorShuffle.py
index 918d6192..3ed21895 100644
--- a/DoorShuffle.py
+++ b/DoorShuffle.py
@@ -1,22 +1,21 @@
 import RaceRandom as random
 from collections import defaultdict, deque
 import logging
-import operator as op
 import time
 from enum import unique, Flag
 from typing import DefaultDict, Dict, List
 
-from functools import reduce
-from BaseClasses import RegionType, Region, Door, DoorType, Direction, Sector, CrystalBarrier, DungeonInfo
+from BaseClasses import RegionType, Region, Door, DoorType, Direction, Sector, CrystalBarrier, DungeonInfo, dungeon_keys
 from Doors import reset_portals
 from Dungeons import dungeon_regions, region_starts, standard_starts, split_region_starts
-from Dungeons import dungeon_bigs, dungeon_keys, dungeon_hints
+from Dungeons import dungeon_bigs, dungeon_hints
 from Items import ItemFactory
 from RoomData import DoorKind, PairedDoor, reset_rooms
 from DungeonGenerator import ExplorationState, convert_regions, generate_dungeon, pre_validate, determine_required_paths, drop_entrances
 from DungeonGenerator import create_dungeon_builders, split_dungeon_builder, simple_dungeon_builder, default_dungeon_entrances
 from DungeonGenerator import dungeon_portals, dungeon_drops, GenerationException
-from KeyDoorShuffle import analyze_dungeon, validate_vanilla_key_logic, build_key_layout, validate_key_layout
+from KeyDoorShuffle import analyze_dungeon, build_key_layout, validate_key_layout
+from Utils import ncr, kth_combination
 
 
 def link_doors(world, player):
@@ -102,6 +101,8 @@ def link_doors_main(world, player):
             connect_portal(portal, world, player)
     if not world.doorShuffle[player] == 'vanilla':
         fix_big_key_doors_with_ugly_smalls(world, player)
+    else:
+        unmark_ugly_smalls(world, player)
     if world.doorShuffle[player] == 'vanilla':
         for entrance, ext in open_edges:
             connect_two_way(world, entrance, ext, player)
@@ -214,8 +215,8 @@ def vanilla_key_logic(world, player):
         analyze_dungeon(key_layout, world, player)
         world.key_logic[player][builder.name] = key_layout.key_logic
         log_key_logic(builder.name, key_layout.key_logic)
-    if world.shuffle[player] == 'vanilla' and world.accessibility[player] == 'items' and not world.retro[player] and not world.keydropshuffle[player]:
-        validate_vanilla_key_logic(world, player)
+    # if world.shuffle[player] == 'vanilla' and world.accessibility[player] == 'items' and not world.retro[player] and not world.keydropshuffle[player]:
+    #     validate_vanilla_key_logic(world, player)
 
 
 # some useful functions
@@ -317,6 +318,13 @@ def connect_one_way(world, entrancename, exitname, player):
         y.dest = x
 
 
+def unmark_ugly_smalls(world, player):
+    for d in ['Eastern Hint Tile Blocked Path SE', 'Eastern Darkness S', 'Thieves Hallway SE', 'Mire Left Bridge S',
+              'TR Lava Escape SE', 'GT Hidden Spikes SE']:
+        door = world.get_door(d, player)
+        door.smallKey = False
+
+
 def fix_big_key_doors_with_ugly_smalls(world, player):
     remove_ugly_small_key_doors(world, player)
     unpair_big_key_doors(world, player)
@@ -503,6 +511,9 @@ def analyze_portals(world, player):
                 raise Exception('please inspect this case')
         if len(reachable_portals) == 1:
             info.sole_entrance = reachable_portals[0]
+        if world.intensity[player] < 2 and world.doorShuffle[player] == 'basic' and dungeon == 'Desert Palace':
+            if len(inaccessible_portals) == 1 and inaccessible_portals[0] == 'Desert Back':
+                info.required_passage.clear()  # can't make a passage at this intensity level, something else must exit
         info_map[dungeon] = info
 
     for dungeon, info in info_map.items():
@@ -1104,9 +1115,9 @@ def assign_cross_keys(dungeon_builders, world, player):
     logger.debug('Cross Dungeon: Keys unable to assign in pool %s', remaining)
 
     # Last Step: Adjust Small Key Dungeon Pool
-    if not world.retro[player]:
-        for name, builder in dungeon_builders.items():
-            reassign_key_doors(builder, world, player)
+    for name, builder in dungeon_builders.items():
+        reassign_key_doors(builder, world, player)
+        if not world.retro[player]:
             log_key_logic(builder.name, world.key_logic[player][builder.name])
             actual_chest_keys = max(builder.key_doors_num - builder.key_drop_cnt, 0)
             dungeon = world.get_dungeon(name, player)
@@ -1580,28 +1591,6 @@ def find_key_door_candidates(region, checked, world, player):
     return candidates, checked_doors
 
 
-def kth_combination(k, l, r):
-    if r == 0:
-        return []
-    elif len(l) == r:
-        return l
-    else:
-        i = ncr(len(l)-1, r-1)
-        if k < i:
-            return l[0:1] + kth_combination(k, l[1:], r-1)
-        else:
-            return kth_combination(k-i, l[1:], r)
-
-
-def ncr(n, r):
-    if r == 0:
-        return 1
-    r = min(r, n-r)
-    numerator = reduce(op.mul, range(n, n-r, -1), 1)
-    denominator = reduce(op.mul, range(1, r+1), 1)
-    return numerator / denominator
-
-
 def reassign_key_doors(builder, world, player):
     logger = logging.getLogger('')
     logger.debug('Key doors for %s', builder.name)
@@ -1830,6 +1819,10 @@ def find_inaccessible_regions(world, player):
                 if connect.type is not RegionType.Dungeon or connect.name.endswith(' Portal'):
                     queue.append(connect)
     world.inaccessible_regions[player].extend([r.name for r in all_regions.difference(visited_regions) if valid_inaccessible_region(r)])
+    if world.mode[player] == 'inverted':
+        ledge = world.get_region('Hyrule Castle Ledge', 1)
+        if any(x for x in ledge.exits if x.connected_region.name == 'Agahnims Tower Portal'):
+            world.inaccessible_regions[player].append('Hyrule Castle Ledge')
     logger = logging.getLogger('')
     logger.debug('Inaccessible Regions:')
     for r in world.inaccessible_regions[player]:
diff --git a/DungeonGenerator.py b/DungeonGenerator.py
index 06af10da..948115f3 100644
--- a/DungeonGenerator.py
+++ b/DungeonGenerator.py
@@ -39,14 +39,15 @@ def pre_validate(builder, entrance_region_names, split_dungeon, world, player):
     proposed_map = {}
     doors_to_connect = {}
     all_regions = set()
-    bk_needed = False
     bk_special = False
     for sector in builder.sectors:
         for door in sector.outstanding_doors:
             doors_to_connect[door.name] = door
         all_regions.update(sector.regions)
-        bk_needed = bk_needed or determine_if_bk_needed(sector, split_dungeon, world, player)
-        bk_special = bk_special or check_for_special(sector)
+        bk_special |= check_for_special(sector.regions)
+    bk_needed = False
+    for sector in builder.sectors:
+        bk_needed |= determine_if_bk_needed(sector, split_dungeon, bk_special, world, player)
     paths = determine_paths_for_dungeon(world, player, all_regions, builder.name)
     dungeon, hangers, hooks = gen_dungeon_info(builder.name, builder.sectors, entrance_regions, all_regions,
                                                proposed_map, doors_to_connect, bk_needed, bk_special, world, player)
@@ -101,19 +102,27 @@ def generate_dungeon_find_proposal(builder, entrance_region_names, split_dungeon
     excluded = {}
     for region in entrance_regions:
         portal = next((x for x in world.dungeon_portals[player] if x.door.entrance.parent_region == region), None)
-        if portal and portal.destination:
-            excluded[region] = None
+        if portal:
+            if portal.destination:
+                excluded[region] = None
+            elif len(entrance_regions) > 1:
+                p_region = portal.door.entrance.connected_region
+                access_region = next(x.parent_region for x in p_region.entrances
+                                     if x.parent_region.type in [RegionType.LightWorld, RegionType.DarkWorld])
+                if access_region.name in world.inaccessible_regions[player]:
+                    excluded[region] = None
     entrance_regions = [x for x in entrance_regions if x not in excluded.keys()]
     doors_to_connect = {}
     all_regions = set()
-    bk_needed = False
     bk_special = False
     for sector in builder.sectors:
         for door in sector.outstanding_doors:
             doors_to_connect[door.name] = door
         all_regions.update(sector.regions)
-        bk_needed = bk_needed or determine_if_bk_needed(sector, split_dungeon, world, player)
-        bk_special = bk_special or check_for_special(sector)
+        bk_special |= check_for_special(sector.regions)
+    bk_needed = False
+    for sector in builder.sectors:
+        bk_needed |= determine_if_bk_needed(sector, split_dungeon, bk_special, world, player)
     proposed_map = {}
     choices_master = [[]]
     depth = 0
@@ -187,8 +196,8 @@ def generate_dungeon_find_proposal(builder, entrance_region_names, split_dungeon
     return proposed_map
 
 
-def determine_if_bk_needed(sector, split_dungeon, world, player):
-    if not split_dungeon:
+def determine_if_bk_needed(sector, split_dungeon, bk_special, world, player):
+    if not split_dungeon or bk_special:
         for region in sector.regions:
             for ext in region.exits:
                 door = world.check_for_door(ext.name, player)
@@ -197,8 +206,8 @@ def determine_if_bk_needed(sector, split_dungeon, world, player):
     return False
 
 
-def check_for_special(sector):
-    for region in sector.regions:
+def check_for_special(regions):
+    for region in regions:
         for loc in region.locations:
             if loc.forced_big_key():
                 return True
@@ -417,6 +426,8 @@ def check_valid(name, dungeon, hangers, hooks, proposed_map, doors_to_connect, a
     # origin has no more hooks, but not all doors have been proposed
     if not world.bigkeyshuffle[player]:
         possible_bks = len(dungeon['Origin'].possible_bk_locations)
+        if bk_special and check_for_special(dungeon['Origin'].visited_regions):
+            possible_bks = 1
         true_origin_hooks = [x for x in dungeon['Origin'].hooks.keys() if not x.bigKey or possible_bks > 0 or not bk_needed]
         if len(true_origin_hooks) == 0 and len(proposed_map.keys()) < len(doors_to_connect):
             return False
@@ -450,7 +461,8 @@ def check_valid(name, dungeon, hangers, hooks, proposed_map, doors_to_connect, a
     bk_possible = not bk_needed or (world.bigkeyshuffle[player] and not bk_special)
     for piece in dungeon.values():
         all_visited.update(piece.visited_regions)
-        if not bk_possible and len(piece.possible_bk_locations) > 0:
+        if ((not bk_possible and len(piece.possible_bk_locations) > 0) or
+           (bk_special and check_for_special(piece.visited_regions))):
             bk_possible = True
     if len(all_regions.difference(all_visited)) > 0:
         return False
@@ -807,6 +819,10 @@ class ExplorationState(object):
         self.dungeon = dungeon
         self.pinball_used = False
 
+        self.prize_door_set = {}
+        self.prize_doors = []
+        self.prize_doors_opened = False
+
     def copy(self):
         ret = ExplorationState(dungeon=self.dungeon)
         ret.unattached_doors = list(self.unattached_doors)
@@ -833,6 +849,10 @@ class ExplorationState(object):
         ret.non_door_entrances = list(self.non_door_entrances)
         ret.dungeon = self.dungeon
         ret.pinball_used = self.pinball_used
+
+        ret.prize_door_set = dict(self.prize_door_set)
+        ret.prize_doors = list(self.prize_doors)
+        ret.prize_doors_opened = self.prize_doors_opened
         return ret
 
     def next_avail_door(self):
@@ -842,6 +862,8 @@ class ExplorationState(object):
         return exp_door
 
     def visit_region(self, region, key_region=None, key_checks=False, bk_Flag=False):
+        if region.type != RegionType.Dungeon:
+            self.crystal = CrystalBarrier.Orange
         if self.crystal == CrystalBarrier.Either:
             if region not in self.visited_blue:
                 self.visited_blue.append(region)
@@ -868,6 +890,8 @@ class ExplorationState(object):
                 if location.name in flooded_keys_reverse.keys() and self.location_found(
                      flooded_keys_reverse[location.name]):
                     self.perform_event(flooded_keys_reverse[location.name], key_region)
+                if '- Prize' in location.name:
+                    self.prize_received = True
 
     def flooded_key_check(self, location):
         if location.name not in flooded_keys.keys():
@@ -1103,9 +1127,9 @@ def valid_region_to_explore_in_regions(region, all_regions, world, player):
 def valid_region_to_explore(region, name, world, player):
     if region is None:
         return False
-    return (region.type == RegionType.Dungeon and region.dungeon.name in name)\
-        or region.name in world.inaccessible_regions[player]\
-        or (region.name == 'Hyrule Castle Ledge' and world.mode[player] == 'standard')
+    return ((region.type == RegionType.Dungeon and region.dungeon and region.dungeon.name in name)
+        or region.name in world.inaccessible_regions[player]
+        or (region.name == 'Hyrule Castle Ledge' and world.mode[player] == 'standard'))
 
 
 def get_doors(world, region, player):
@@ -1291,13 +1315,16 @@ def create_dungeon_builders(all_sectors, connections_tuple, world, player,
                 sanc_builder = random.choice(lw_builders)
                 assign_sector(sanc, sanc_builder, candidate_sectors, global_pole)
 
+        bow_sectors, retro_std_flag = {}, world.retro[player] and world.mode[player] == 'standard'
         free_location_sectors = {}
         crystal_switches = {}
         crystal_barriers = {}
         polarized_sectors = {}
         neutral_sectors = {}
         for sector in candidate_sectors:
-            if sector.chest_locations > 0:
+            if retro_std_flag and 'Bow' in sector.item_logic:  # these need to be distributed outside of HC
+                bow_sectors[sector] = None
+            elif sector.chest_locations > 0:
                 free_location_sectors[sector] = None
             elif sector.c_switch:
                 crystal_switches[sector] = None
@@ -1307,6 +1334,8 @@ def create_dungeon_builders(all_sectors, connections_tuple, world, player,
                 neutral_sectors[sector] = None
             else:
                 polarized_sectors[sector] = None
+        if bow_sectors:
+            assign_bow_sectors(dungeon_map, bow_sectors, global_pole)
         assign_location_sectors(dungeon_map, free_location_sectors, global_pole)
         leftover = assign_crystal_switch_sectors(dungeon_map, crystal_switches, crystal_barriers, global_pole)
         ensure_crystal_switches_reachable(dungeon_map, leftover, polarized_sectors, crystal_barriers, global_pole)
@@ -1472,6 +1501,9 @@ def define_sector_features(sectors):
                         sector.blue_barrier = True
                     if door.bigKey:
                         sector.bk_required = True
+            if region.name in ['PoD Mimics 2', 'PoD Bow Statue Right', 'PoD Mimics 1', 'GT Mimics 1', 'GT Mimics 2',
+                               'Eastern Single Eyegore', 'Eastern Duo Eyegores']:
+                sector.item_logic.add('Bow')
 
 
 def assign_sector(sector, dungeon, candidate_sectors, global_pole):
@@ -1522,6 +1554,19 @@ def find_sector(r_name, sectors):
     return None
 
 
+def assign_bow_sectors(dungeon_map, bow_sectors, global_pole):
+    sector_list = list(bow_sectors)
+    random.shuffle(sector_list)
+    population = []
+    for name in dungeon_map:
+        if name != 'Hyrule Castle':
+            population.append(name)
+    choices = random.choices(population, k=len(sector_list))
+    for i, choice in enumerate(choices):
+        builder = dungeon_map[choice]
+        assign_sector(sector_list[i], builder, bow_sectors, global_pole)
+
+
 def assign_location_sectors(dungeon_map, free_location_sectors, global_pole):
     valid = False
     choices = None
@@ -3275,6 +3320,7 @@ def check_for_valid_layout(builder, sector_list, builder_info):
                     possible_regions.add(portal.door.entrance.parent_region.name)
             if builder.name in dungeon_drops.keys():
                 possible_regions.update(dungeon_drops[builder.name])
+            independents = find_independent_entrances(possible_regions, world, player)
             for name, split_build in builder.split_dungeon_map.items():
                 name_bits = name.split(" ")
                 orig_name = " ".join(name_bits[:-1])
@@ -3287,7 +3333,8 @@ def check_for_valid_layout(builder, sector_list, builder_info):
                             if r_name not in entrance_regions:
                                 entrance_regions.append(r_name)
                 # entrance_regions = [x for x in entrance_regions if x not in split_check_entrance_invalid]
-                proposal = generate_dungeon_find_proposal(split_build, entrance_regions, True, world, player)
+                split = any(x for x in independents if x not in entrance_regions)
+                proposal = generate_dungeon_find_proposal(split_build, entrance_regions, split, world, player)
                 # record split proposals
                 builder.valid_proposal[name] = proposal
             builder.exception_list = list(sector_list)
@@ -3302,6 +3349,32 @@ def check_for_valid_layout(builder, sector_list, builder_info):
         return len(unreached_doors) == 0, unreached_doors
 
 
+def find_independent_entrances(entrance_regions, world, player):
+    independents = set()
+    for region in entrance_regions:
+        portal = next((x for x in world.dungeon_portals[player] if x.door.entrance.parent_region.name == region), None)
+        if portal:
+            if portal.destination:
+                continue
+            elif len(entrance_regions) > 1:
+                p_region = portal.door.entrance.connected_region
+                access_region = next(x.parent_region for x in p_region.entrances
+                                     if x.parent_region.type in [RegionType.LightWorld, RegionType.DarkWorld])
+                if access_region.name in world.inaccessible_regions[player]:
+                    continue
+        else:
+            r = world.get_region(region, player)
+            access_region = next(x.parent_region for x in r.entrances
+                                 if x.parent_region.type in [RegionType.LightWorld, RegionType.DarkWorld]
+                                 or x.parent_region.name == 'Sewer Drop')
+            if access_region.name == 'Sewer Drop':
+                access_region = next(x.parent_region for x in access_region.entrances)
+            if access_region.name in world.inaccessible_regions[player]:
+                continue
+        independents.add(region)
+    return independents
+
+
 def resolve_equations(builder, sector_list):
     unreached_doors = defaultdict(list)
     equations = {x: y for x, y in copy_door_equations(builder, sector_list).items() if len(y) > 0}
diff --git a/Dungeons.py b/Dungeons.py
index 81fc4941..73f53794 100644
--- a/Dungeons.py
+++ b/Dungeons.py
@@ -375,13 +375,6 @@ flexible_starts = {
     'Skull Woods': ['Skull Left Drop', 'Skull Pinball']
 }
 
-default_key_counts = {
-    'Hyrule Castle': 1, 'Eastern Palace': 0, 'Desert Palace': 1,
-    'Tower of Hera': 1, 'Agahnims Tower': 2, 'Palace of Darkness': 6,
-    'Swamp Palace': 1, 'Skull Woods': 3, 'Thieves Town': 1,
-    'Ice Palace': 2, 'Misery Mire': 3, 'Turtle Rock': 4, 'Ganons Tower': 4
-}
-
 dungeon_keys = {
     'Hyrule Castle': 'Small Key (Escape)',
     'Eastern Palace': 'Small Key (Eastern Palace)',
@@ -414,6 +407,19 @@ dungeon_bigs = {
     'Ganons Tower': 'Big Key (Ganons Tower)'
 }
 
+dungeon_prize = {
+    'Eastern Palace': 'Eastern Palace - Prize',
+    'Desert Palace': 'Desert Palace - Prize',
+    'Tower of Hera': 'Tower of Hera - Prize',
+    'Palace of Darkness': 'Palace of Darkness - Prize',
+    'Swamp Palace': 'Swamp Palace - Prize',
+    'Skull Woods': 'Skull Woods - Prize',
+    'Thieves Town': 'Thieves Town - Prize',
+    'Ice Palace': 'Ice Palace - Prize',
+    'Misery Mire': 'Misery Mire - Prize',
+    'Turtle Rock': 'Turtle Rock - Prize',
+}
+
 dungeon_hints = {
     'Hyrule Castle': 'in Hyrule Castle',
     'Eastern Palace': 'in Eastern Palace',
diff --git a/EntranceShuffle.py b/EntranceShuffle.py
index 1c1a6ab8..7e5dcdd3 100644
--- a/EntranceShuffle.py
+++ b/EntranceShuffle.py
@@ -2120,10 +2120,11 @@ def connect_doors(world, doors, targets, player):
     """This works inplace"""
     random.shuffle(doors)
     random.shuffle(targets)
-    while doors:
-        door = doors.pop()
-        target = targets.pop()
+    placing = min(len(doors), len(targets))
+    for door, target in zip(doors, targets):
         connect_entrance(world, door, target, player)
+    doors[:] = doors[placing:]
+    targets[:] = targets[placing:]
 
 
 def skull_woods_shuffle(world, player):
diff --git a/Fill.py b/Fill.py
index 7572b350..c42b6251 100644
--- a/Fill.py
+++ b/Fill.py
@@ -1,4 +1,6 @@
 import RaceRandom as random
+import collections
+import itertools
 import logging
 
 from BaseClasses import CollectionState
@@ -211,7 +213,7 @@ def fill_restrictive(world, base_state, locations, itempool, keys_in_itempool =
                             and valid_key_placement(item_to_place, location, itempool if (keys_in_itempool and keys_in_itempool[item_to_place.player]) else world.itempool, world):
                         spot_to_fill = location
                         break
-                    elif item_to_place.smallkey or item_to_place.bigkey:
+                    if item_to_place.smallkey or item_to_place.bigkey:
                         location.item = None
 
                 if spot_to_fill is None:
@@ -221,7 +223,10 @@ def fill_restrictive(world, base_state, locations, itempool, keys_in_itempool =
                         if world.accessibility[item_to_place.player] != 'none':
                             logging.getLogger('').warning('Not all items placed. Game beatable anyway. (Could not place %s)' % item_to_place)
                         continue
-                    raise FillError('No more spots to place %s' % item_to_place)
+                    spot_to_fill = last_ditch_placement(item_to_place, locations, world, maximum_exploration_state,
+                                                        base_state, itempool, keys_in_itempool, single_player_placement)
+                    if spot_to_fill is None:
+                        raise FillError('No more spots to place %s' % item_to_place)
 
                 world.push_item(spot_to_fill, item_to_place, False)
                 track_outside_keys(item_to_place, spot_to_fill, world)
@@ -250,9 +255,7 @@ def valid_key_placement(item, location, itempool, world):
 def track_outside_keys(item, location, world):
     if not item.smallkey:
         return
-    item_dungeon = item.name.split('(')[1][:-1]
-    if item_dungeon == 'Escape':
-        item_dungeon = 'Hyrule Castle'
+    item_dungeon = item.dungeon
     if location.player == item.player:
         loc_dungeon = location.parent_region.dungeon
         if loc_dungeon and loc_dungeon.name == item_dungeon:
@@ -260,6 +263,80 @@ def track_outside_keys(item, location, world):
     world.key_logic[item.player][item_dungeon].outside_keys += 1
 
 
+def last_ditch_placement(item_to_place, locations, world, state, base_state, itempool,
+                         keys_in_itempool=None, single_player_placement=False):
+    def location_preference(loc):
+        if not loc.item.advancement:
+            return 1
+        if loc.item.type and loc.item.type != 'Sword':
+            if loc.item.type in ['Map', 'Compass']:
+                return 2
+            else:
+                return 3
+        return 4
+
+    if item_to_place.type == 'Crystal':
+        possible_swaps = [x for x in state.locations_checked if x.item.type == 'Crystal']
+    else:
+        possible_swaps = [x for x in state.locations_checked
+                          if x.item.type not in ['Event', 'Crystal'] and not x.forced_item]
+    swap_locations = sorted(possible_swaps, key=location_preference)
+
+    for location in swap_locations:
+        old_item = location.item
+        new_pool = list(itempool) + [old_item]
+        new_spot = find_spot_for_item(item_to_place, [location], world, base_state, new_pool,
+                                      keys_in_itempool, single_player_placement)
+        if new_spot:
+            restore_item = new_spot.item
+            new_spot.item = item_to_place
+            swap_spot = find_spot_for_item(old_item, locations, world, base_state, itempool,
+                                           keys_in_itempool, single_player_placement)
+            if swap_spot:
+                logging.getLogger('').debug(f'Swapping {old_item} for {item_to_place}')
+                world.push_item(swap_spot, old_item, False)
+                swap_spot.event = True
+                locations.remove(swap_spot)
+                locations.append(new_spot)
+                return new_spot
+            else:
+                new_spot.item = restore_item
+        else:
+            location.item = old_item
+    return None
+
+
+def find_spot_for_item(item_to_place, locations, world, base_state, pool,
+                       keys_in_itempool=None, single_player_placement=False):
+    def sweep_from_pool():
+        new_state = base_state.copy()
+        for item in pool:
+            new_state.collect(item, True)
+        new_state.sweep_for_events()
+        return new_state
+    for location in locations:
+        maximum_exploration_state = sweep_from_pool()
+        perform_access_check = True
+        old_item = None
+        if world.accessibility[item_to_place.player] == 'none':
+            perform_access_check = not world.has_beaten_game(maximum_exploration_state, item_to_place.player) if single_player_placement else not world.has_beaten_game(maximum_exploration_state)
+
+        if item_to_place.smallkey or item_to_place.bigkey:  # a better test to see if a key can go there
+            old_item = location.item
+            location.item = item_to_place
+            test_state = maximum_exploration_state.copy()
+            test_state.stale[item_to_place.player] = True
+        else:
+            test_state = maximum_exploration_state
+        if (not single_player_placement or location.player == item_to_place.player) \
+             and location.can_fill(test_state, item_to_place, perform_access_check) \
+             and valid_key_placement(item_to_place, location, pool if (keys_in_itempool and keys_in_itempool[item_to_place.player]) else world.itempool, world):
+            return location
+        if item_to_place.smallkey or item_to_place.bigkey:
+            location.item = old_item
+    return None
+
+
 def distribute_items_restrictive(world, gftower_trash=False, fill_locations=None):
     # If not passed in, then get a shuffled list of locations to fill in
     if not fill_locations:
@@ -420,9 +497,8 @@ def sell_keys(world, player):
 
 def balance_multiworld_progression(world):
     state = CollectionState(world)
-    checked_locations = []
-    unchecked_locations = world.get_locations().copy()
-    random.shuffle(unchecked_locations)
+    checked_locations = set()
+    unchecked_locations = set(world.get_locations())
 
     reachable_locations_count = {}
     for player in range(1, world.players + 1):
@@ -430,7 +506,7 @@ def balance_multiworld_progression(world):
 
     def get_sphere_locations(sphere_state, locations):
         sphere_state.sweep_for_events(key_only=True, locations=locations)
-        return [loc for loc in locations if sphere_state.can_reach(loc) and sphere_state.not_flooding_a_key(sphere_state.world, loc)]
+        return {loc for loc in locations if sphere_state.can_reach(loc) and sphere_state.not_flooding_a_key(sphere_state.world, loc)}
 
     while True:
         sphere_locations = get_sphere_locations(state, unchecked_locations)
@@ -441,38 +517,42 @@ def balance_multiworld_progression(world):
         if checked_locations:
             threshold = max(reachable_locations_count.values()) - 20
 
-            balancing_players = [player for player, reachables in reachable_locations_count.items() if reachables < threshold]
-            if balancing_players is not None and len(balancing_players) > 0:
+            balancing_players = {player for player, reachables in reachable_locations_count.items() if reachables < threshold}
+            if balancing_players:
                 balancing_state = state.copy()
                 balancing_unchecked_locations = unchecked_locations.copy()
                 balancing_reachables = reachable_locations_count.copy()
                 balancing_sphere = sphere_locations.copy()
-                candidate_items = []
+                candidate_items = collections.defaultdict(set)
                 while True:
                     for location in balancing_sphere:
                         if location.event and (world.keyshuffle[location.item.player] or not location.item.smallkey) and (world.bigkeyshuffle[location.item.player] or not location.item.bigkey):
                             balancing_state.collect(location.item, True, location)
-                            if location.item.player in balancing_players and not location.locked:
-                                candidate_items.append(location)
+                            player = location.item.player
+                            if player in balancing_players and not location.locked and location.player != player:
+                                candidate_items[player].add(location)
                     balancing_sphere = get_sphere_locations(balancing_state, balancing_unchecked_locations)
                     for location in balancing_sphere:
                         balancing_unchecked_locations.remove(location)
                         balancing_reachables[location.player] += 1
-                    if world.has_beaten_game(balancing_state) or all([reachables >= threshold for reachables in balancing_reachables.values()]):
+                    if world.has_beaten_game(balancing_state) or all(reachables >= threshold for reachables in balancing_reachables.values()):
                         break
                     elif not balancing_sphere:
                         raise RuntimeError('Not all required items reachable. Something went terribly wrong here.')
 
-                unlocked_locations = [l for l in unchecked_locations if l not in balancing_unchecked_locations]
+                unlocked_locations = collections.defaultdict(set)
+                for l in unchecked_locations:
+                    if l not in balancing_unchecked_locations:
+                        unlocked_locations[l.player].add(l)
                 items_to_replace = []
                 for player in balancing_players:
-                    locations_to_test = [l for l in unlocked_locations if l.player == player]
-                    # only replace items that end up in another player's world
-                    items_to_test = [l for l in candidate_items if l.item.player == player and l.player != player]
+                    locations_to_test = unlocked_locations[player]
+                    items_to_test = candidate_items[player]
                     while items_to_test:
                         testing = items_to_test.pop()
                         reducing_state = state.copy()
-                        for location in [*[l for l in items_to_replace if l.item.player == player], *items_to_test]:
+                        for location in itertools.chain((l for l in items_to_replace if l.item.player == player),
+                                                        items_to_test):
                             reducing_state.collect(location.item, True, location)
 
                         reducing_state.sweep_for_events(locations=locations_to_test)
@@ -486,33 +566,44 @@ def balance_multiworld_progression(world):
                                 items_to_replace.append(testing)
 
                 replaced_items = False
-                replacement_locations = [l for l in checked_locations if not l.event and not l.locked]
+                # sort then shuffle to maintain deterministic behaviour,
+                # while allowing use of set for better algorithm growth behaviour elsewhere
+                replacement_locations = sorted((l for l in checked_locations if not l.event and not l.locked),
+                                               key=lambda loc: (loc.name, loc.player))
+                random.shuffle(replacement_locations)
+                items_to_replace.sort(key=lambda item: (item.name, item.player))
+                random.shuffle(items_to_replace)
                 while replacement_locations and items_to_replace:
-                    new_location = replacement_locations.pop()
                     old_location = items_to_replace.pop()
+                    for new_location in replacement_locations:
+                        if (new_location.can_fill(state, old_location.item, False) and
+                           old_location.can_fill(state, new_location.item, False)):
+                            replacement_locations.remove(new_location)
+                            new_location.item, old_location.item = old_location.item, new_location.item
+                            if world.shopsanity[new_location.player]:
+                                check_shop_swap(new_location)
+                            if world.shopsanity[old_location.player]:
+                                check_shop_swap(old_location)
+                            new_location.event, old_location.event = True, False
+                            logging.debug(f"Progression balancing moved {new_location.item} to {new_location}, "
+                                          f"displacing {old_location.item} into {old_location}")
+                            state.collect(new_location.item, True, new_location)
+                            replaced_items = True
+                            break
+                    else:
+                        logging.warning(f"Could not Progression Balance {old_location.item}")
 
-                    while not new_location.can_fill(state, old_location.item, False) or (new_location.item and not old_location.can_fill(state, new_location.item, False)):
-                        replacement_locations.insert(0, new_location)
-                        new_location = replacement_locations.pop()
-
-                    new_location.item, old_location.item = old_location.item, new_location.item
-                    if world.shopsanity[new_location.player]:
-                        check_shop_swap(new_location)
-                    if world.shopsanity[old_location.player]:
-                        check_shop_swap(old_location)
-                    new_location.event, old_location.event = True, False
-                    state.collect(new_location.item, True, new_location)
-                    replaced_items = True
                 if replaced_items:
-                    for location in get_sphere_locations(state, [l for l in unlocked_locations if l.player in balancing_players]):
+                    unlocked = {fresh for player in balancing_players for fresh in unlocked_locations[player]}
+                    for location in get_sphere_locations(state, unlocked):
                         unchecked_locations.remove(location)
                         reachable_locations_count[location.player] += 1
-                        sphere_locations.append(location)
+                        sphere_locations.add(location)
 
         for location in sphere_locations:
             if location.event and (world.keyshuffle[location.item.player] or not location.item.smallkey) and (world.bigkeyshuffle[location.item.player] or not location.item.bigkey):
                 state.collect(location.item, True, location)
-        checked_locations.extend(sphere_locations)
+        checked_locations |= sphere_locations
 
         if world.has_beaten_game(state):
             break
@@ -651,7 +742,7 @@ def balance_money_progression(world):
                 if room not in rooms_visited[player] and world.get_region(room, player) in state.reachable_regions[player]:
                     wallet[player] += income
                     rooms_visited[player].add(room)
-        if checked_locations:
+        if checked_locations or len(unchecked_locations) == 0:
             if world.has_beaten_game(state):
                 done = True
                 continue
@@ -661,11 +752,11 @@ def balance_money_progression(world):
             solvent = set()
             insolvent = set()
             for player in range(1, world.players+1):
-                if wallet[player] >= sphere_costs[player] > 0:
+                if wallet[player] >= sphere_costs[player] >= 0:
                     solvent.add(player)
                 if sphere_costs[player] > 0 and sphere_costs[player] > wallet[player]:
                     insolvent.add(player)
-            if len(solvent) == 0:
+            if len([p for p in solvent if len(locked_by_money[p]) > 0]) == 0:
                 target_player = min(insolvent, key=lambda p: sphere_costs[p]-wallet[p])
                 difference = sphere_costs[target_player]-wallet[target_player]
                 logger.debug(f'Money balancing needed: Player {target_player} short {difference}')
@@ -705,7 +796,7 @@ def balance_money_progression(world):
             for player in solvent:
                 wallet[player] -= sphere_costs[player]
                 for location in locked_by_money[player]:
-                    if location == 'Kiki':
+                    if isinstance(location, str) and location == 'Kiki':
                         kiki_paid[player] = True
                     else:
                         state.collect(location.item, True, location)
diff --git a/ItemList.py b/ItemList.py
index 2edad3fe..5f5b5e7e 100644
--- a/ItemList.py
+++ b/ItemList.py
@@ -347,11 +347,11 @@ def generate_itempool(world, player):
     # rather than making all hearts/heart pieces progression items (which slows down generation considerably)
     # We mark one random heart container as an advancement item (or 4 heart pieces in expert mode)
     if world.difficulty[player] in ['normal', 'hard'] and not (world.custom and world.customitemarray[player]["heartcontainer"] == 0):
-        [item for item in items if item.name == 'Boss Heart Container'][0].advancement = True
+        next(item for item in items if item.name == 'Boss Heart Container').advancement = True
     elif world.difficulty[player] in ['expert'] and not (world.custom and world.customitemarray[player]["heartpiece"] < 4):
-        adv_heart_pieces = [item for item in items if item.name == 'Piece of Heart'][0:4]
-        for hp in adv_heart_pieces:
-            hp.advancement = True
+        adv_heart_pieces = (item for item in items if item.name == 'Piece of Heart')
+        for i in range(4):
+            next(adv_heart_pieces).advancement = True
 
     beeweights = {'0': {None: 100},
                   '1': {None: 75, 'trap': 25},
diff --git a/KeyDoorShuffle.py b/KeyDoorShuffle.py
index ca4a7f10..cf18f4f4 100644
--- a/KeyDoorShuffle.py
+++ b/KeyDoorShuffle.py
@@ -2,9 +2,9 @@ import itertools
 import logging
 from collections import defaultdict, deque
 
-from BaseClasses import DoorType
+from BaseClasses import DoorType, dungeon_keys, KeyRuleType, RegionType
 from Regions import dungeon_events
-from Dungeons import dungeon_keys, dungeon_bigs, default_key_counts
+from Dungeons import dungeon_keys, dungeon_bigs, dungeon_prize
 from DungeonGenerator import ExplorationState, special_big_key_doors
 
 
@@ -25,6 +25,8 @@ class KeyLayout(object):
         self.all_locations = set()
         self.item_locations = set()
 
+        self.found_doors = set()
+        self.prize_relevant = False
         # bk special?
         # bk required? True if big chests or big doors exists
 
@@ -35,6 +37,7 @@ class KeyLayout(object):
         self.max_chests = calc_max_chests(builder, self, world, player)
         self.all_locations = set()
         self.item_locations = set()
+        self.prize_relevant = False
 
 
 class KeyLogic(object):
@@ -54,10 +57,11 @@ class KeyLogic(object):
         self.location_rules = {}
         self.outside_keys = 0
         self.dungeon = dungeon_name
+        self.sm_doors = {}
 
     def check_placement(self, unplaced_keys, big_key_loc=None):
         for rule in self.placement_rules:
-            if not rule.is_satisfiable(self.outside_keys, unplaced_keys):
+            if not rule.is_satisfiable(self.outside_keys, unplaced_keys, big_key_loc):
                 return False
             if big_key_loc:
                 for rule_a, rule_b in itertools.combinations(self.placement_rules, 2):
@@ -65,6 +69,15 @@ class KeyLogic(object):
                         return False
         return True
 
+    def reset(self):
+        self.door_rules.clear()
+        self.bk_restricted.clear()
+        self.bk_locked.clear()
+        self.sm_restricted.clear()
+        self.bk_doors.clear()
+        self.bk_chests.clear()
+        self.placement_rules.clear()
+
 
 class DoorRules(object):
 
@@ -79,6 +92,8 @@ class DoorRules(object):
         self.small_location = None
         self.opposite = None
 
+        self.new_rules = {}  # keyed by type, or type+lock_item -> number
+
 
 class LocationRule(object):
     def __init__(self):
@@ -101,6 +116,7 @@ class PlacementRule(object):
         self.needed_keys_w_bk = None
         self.needed_keys_wo_bk = None
         self.check_locations_w_bk = None
+        self.special_bk_avail = False
         self.check_locations_wo_bk = None
         self.bk_relevant = True
         self.key_reduced = False
@@ -112,6 +128,10 @@ class PlacementRule(object):
         rule_locations = rule.check_locations_wo_bk if rule_blocked else rule.check_locations_w_bk
         if check_locations is None or rule_locations is None:
             return False
+        if not bk_blocked and big_key_loc not in check_locations:  # bk is not available, so rule doesn't apply
+            return False
+        if not rule_blocked and big_key_loc not in rule_locations:  # bk is not available, so rule doesn't apply
+            return False
         check_locations = check_locations - {big_key_loc}
         rule_locations = rule_locations - {big_key_loc}
         threshold = self.needed_keys_wo_bk if bk_blocked else self.needed_keys_w_bk
@@ -134,13 +154,23 @@ class PlacementRule(object):
                 left -= rule_needed
         return False
 
-    def is_satisfiable(self, outside_keys, unplaced_keys):
+    def is_satisfiable(self, outside_keys, unplaced_keys, big_key_loc):
         bk_blocked = False
         if self.bk_conditional_set:
             for loc in self.bk_conditional_set:
                 if loc.item and loc.item.bigkey:
                     bk_blocked = True
                     break
+        else:
+            def loc_has_bk(l):
+                return (big_key_loc is not None and big_key_loc == l) or (l.item and l.item.bigkey)
+
+            # todo: sometimes the bk avail rule doesn't mean the bk must be avail or this rule is invalid
+            # but sometimes it certainly does
+            # check threshold vs len(check_loc) maybe to determine bk isn't relevant?
+            bk_found = self.special_bk_avail or any(loc for loc in self.check_locations_w_bk if loc_has_bk(loc))
+            if not bk_found:
+                return True
         check_locations = self.check_locations_wo_bk if bk_blocked else self.check_locations_w_bk
         if not bk_blocked and check_locations is None:
             return True
@@ -170,6 +200,8 @@ class KeyCounter(object):
         self.important_location = False
         self.other_locations = {}
         self.important_locations = {}
+        self.prize_doors_opened = False
+        self.prize_received = False
 
     def used_smalls_loc(self, reserve=0):
         return max(self.used_keys + reserve - len(self.key_only_locations), 0)
@@ -209,8 +241,19 @@ def calc_max_chests(builder, key_layout, world, player):
 
 
 def analyze_dungeon(key_layout, world, player):
+    key_layout.key_logic.reset()
     key_layout.key_counters = create_key_counters(key_layout, world, player)
     key_logic = key_layout.key_logic
+    for door in key_layout.proposal:
+        if isinstance(door, tuple):
+            key_logic.sm_doors[door[0]] = door[1]
+            key_logic.sm_doors[door[1]] = door[0]
+        else:
+            if door.dest and door.type != DoorType.SpiralStairs:
+                key_logic.sm_doors[door] = door.dest
+                key_logic.sm_doors[door.dest] = door
+            else:
+                key_logic.sm_doors[door] = None
 
     find_bk_locked_sections(key_layout, world, player)
     key_logic.bk_chests.update(find_big_chest_locations(key_layout.all_chest_locations))
@@ -218,7 +261,9 @@ def analyze_dungeon(key_layout, world, player):
     if world.retro[player] and world.mode[player] != 'standard':
         return
 
-    original_key_counter = find_counter({}, False, key_layout)
+    original_key_counter = find_counter({}, False, key_layout, False)
+    if key_layout.big_key_special and forced_big_key_avail(original_key_counter.other_locations) is not None:
+        original_key_counter = find_counter({}, True, key_layout, False)
     queue = deque([(None, original_key_counter)])
     doors_completed = set()
     visited_cid = set()
@@ -240,25 +285,30 @@ def analyze_dungeon(key_layout, world, player):
         # try to relax the rules here? - smallest requirement that doesn't force a softlock
         child_queue = deque()
         for child in key_counter.child_doors.keys():
-            if not child.bigKey or not key_layout.big_key_special or big_avail:
+            if can_open_door_by_counter(child, key_counter, key_layout, world, player):
                 odd_counter = create_odd_key_counter(child, key_counter, key_layout, world, player)
                 empty_flag = empty_counter(odd_counter)
                 child_queue.append((child, odd_counter, empty_flag))
         while len(child_queue) > 0:
             child, odd_counter, empty_flag = child_queue.popleft()
-            if not child.bigKey and child not in doors_completed:
-                best_counter = find_best_counter(child, odd_counter, key_counter, key_layout, world, player, False, empty_flag)
-                rule = create_rule(best_counter, key_counter, key_layout, world, player)
+            prize_flag = key_counter.prize_doors_opened
+            if child in key_layout.flat_prop and child not in doors_completed:
+                best_counter = find_best_counter(child, key_layout, odd_counter, False, empty_flag)
+                rule = create_rule(best_counter, key_counter, world, player)
+                create_worst_case_rule(rule, best_counter, world, player)
                 check_for_self_lock_key(rule, child, best_counter, key_layout, world, player)
                 bk_restricted_rules(rule, child, odd_counter, empty_flag, key_counter, key_layout, world, player)
                 key_logic.door_rules[child.name] = rule
+            elif not child.bigKey and child not in doors_completed:
+                prize_flag = True
             doors_completed.add(child)
-            next_counter = find_next_counter(child, key_counter, key_layout)
+            next_counter = find_next_counter(child, key_counter, key_layout, prize_flag)
             ctr_id = cid(next_counter, key_layout)
             if ctr_id not in visited_cid:
                 queue.append((child, next_counter))
                 visited_cid.add(ctr_id)
-    check_rules(original_key_counter, key_layout, world, player)
+    # todo: why is this commented out?
+    # check_rules(original_key_counter, key_layout, world, player)
 
     # Flip bk rules if more restrictive, to prevent placing a big key in a softlocking location
     for rule in key_logic.door_rules.values():
@@ -274,6 +324,8 @@ def create_exhaustive_placement_rules(key_layout, world, player):
     key_logic = key_layout.key_logic
     max_ctr = find_max_counter(key_layout)
     for code, key_counter in key_layout.key_counters.items():
+        if skip_key_counter_due_to_prize(key_layout, key_counter):
+            continue  # we have the prize, we are not concerned about this case
         accessible_loc = set()
         accessible_loc.update(key_counter.free_locations)
         accessible_loc.update(key_counter.key_only_locations)
@@ -294,7 +346,9 @@ def create_exhaustive_placement_rules(key_layout, world, player):
                 else:
                     placement_self_lock_adjustment(rule, max_ctr, blocked_loc, key_counter, world, player)
                     rule.check_locations_w_bk = accessible_loc
-                    check_sm_restriction_needed(key_layout, max_ctr, rule, blocked_loc)
+                    if key_layout.big_key_special:
+                        rule.special_bk_avail = forced_big_key_avail(key_counter.important_locations) is not None
+                    # check_sm_restriction_needed(key_layout, max_ctr, rule, blocked_loc)
             else:
                 if big_key_progress(key_counter) and only_sm_doors(key_counter):
                     create_inclusive_rule(key_layout, max_ctr, code, key_counter, blocked_loc, accessible_loc, min_keys, world, player)
@@ -308,6 +362,10 @@ def create_exhaustive_placement_rules(key_layout, world, player):
     refine_location_rules(key_layout)
 
 
+def skip_key_counter_due_to_prize(key_layout, key_counter):
+    return key_layout.prize_relevant and key_counter.prize_received and not key_counter.prize_doors_opened
+
+
 def placement_self_lock_adjustment(rule, max_ctr, blocked_loc, ctr, world, player):
     if len(blocked_loc) == 1 and world.accessibility[player] != 'locations':
         blocked_others = set(max_ctr.other_locations).difference(set(ctr.other_locations))
@@ -320,6 +378,7 @@ def placement_self_lock_adjustment(rule, max_ctr, blocked_loc, ctr, world, playe
             rule.needed_keys_w_bk -= 1
 
 
+# this rule is suspect - commented out usages for now
 def check_sm_restriction_needed(key_layout, max_ctr, rule, blocked):
     if rule.needed_keys_w_bk == key_layout.max_chests + len(max_ctr.key_only_locations):
         key_layout.key_logic.sm_restricted.update(blocked.difference(max_ctr.key_only_locations))
@@ -413,7 +472,8 @@ def refine_placement_rules(key_layout, max_ctr):
                 rule_b = temp
             if rule_a.bk_conditional_set and rule_b.check_locations_w_bk:
                 common_needed = min(rule_a.needed_keys_wo_bk, rule_b.needed_keys_w_bk)
-                if len(rule_b.check_locations_w_bk & rule_a.check_locations_wo_bk) < common_needed:
+                common_locs = len(rule_b.check_locations_w_bk & rule_a.check_locations_wo_bk)
+                if (common_needed - common_locs) * 2 > key_layout.max_chests:
                     key_logic.bk_restricted.update(rule_a.bk_conditional_set)
                     rules_to_remove.append(rule_a)
                     changed = True
@@ -478,7 +538,7 @@ def create_inclusive_rule(key_layout, max_ctr, code, key_counter, blocked_loc, a
     else:
         placement_self_lock_adjustment(rule, max_ctr, blocked_loc, key_counter, world, player)
         rule.check_locations_w_bk = accessible_loc
-        check_sm_restriction_needed(key_layout, max_ctr, rule, blocked_loc)
+        # check_sm_restriction_needed(key_layout, max_ctr, rule, blocked_loc)
         key_logic.placement_rules.append(rule)
         adjust_locations_rules(key_logic, rule, accessible_loc, key_layout, key_counter, max_ctr)
 
@@ -538,6 +598,8 @@ def relative_empty_counter(odd_counter, key_counter):
         return False
     if len(set(odd_counter.free_locations).difference(key_counter.free_locations)) > 0:
         return False
+    if len(set(odd_counter.other_locations).difference(key_counter.other_locations)) > 0:
+        return False
     # important only
     if len(set(odd_counter.important_locations).difference(key_counter.important_locations)) > 0:
         return False
@@ -594,33 +656,50 @@ def unique_child_door_2(child, key_counter):
     return True
 
 
-def find_best_counter(door, odd_counter, key_counter, key_layout, world, player, skip_bk, empty_flag):  # try to waste as many keys as possible?
-    ignored_doors = {door, door.dest} if door is not None else {}
-    finished = False
-    opened_doors = dict(key_counter.open_doors)
-    bk_opened = key_counter.big_key_opened
-    # new_counter = key_counter
-    last_counter = key_counter
-    while not finished:
-        door_set = find_potential_open_doors(last_counter, ignored_doors, key_layout, skip_bk)
-        if door_set is None or len(door_set) == 0:
-            finished = True
-            continue
-        for new_door in door_set:
-            proposed_doors = {**opened_doors, **dict.fromkeys([new_door, new_door.dest])}
-            bk_open = bk_opened or new_door.bigKey
-            new_counter = find_counter(proposed_doors, bk_open, key_layout)
-            bk_open = new_counter.big_key_opened
-            # this means the new_door invalidates the door / leads to the same stuff
-            if not empty_flag and relative_empty_counter(odd_counter, new_counter):
-                ignored_doors.add(new_door)
-            elif empty_flag or key_wasted(new_door, door, last_counter, new_counter, key_layout, world, player):
-                last_counter = new_counter
-                opened_doors = proposed_doors
-                bk_opened = bk_open
-            else:
-                ignored_doors.add(new_door)
-    return last_counter
+# def find_best_counter(door, odd_counter, key_counter, key_layout, world, player, skip_bk, empty_flag):  # try to waste as many keys as possible?
+#     ignored_doors = {door, door.dest} if door is not None else {}
+#     finished = False
+#     opened_doors = dict(key_counter.open_doors)
+#     bk_opened = key_counter.big_key_opened
+#     # new_counter = key_counter
+#     last_counter = key_counter
+#     while not finished:
+#         door_set = find_potential_open_doors(last_counter, ignored_doors, key_layout, skip_bk)
+#         if door_set is None or len(door_set) == 0:
+#             finished = True
+#             continue
+#         for new_door in door_set:
+#             proposed_doors = {**opened_doors, **dict.fromkeys([new_door, new_door.dest])}
+#             bk_open = bk_opened or new_door.bigKey
+#             new_counter = find_counter(proposed_doors, bk_open, key_layout)
+#             bk_open = new_counter.big_key_opened
+#             # this means the new_door invalidates the door / leads to the same stuff
+#             if not empty_flag and relative_empty_counter(odd_counter, new_counter):
+#                 ignored_doors.add(new_door)
+#             elif empty_flag or key_wasted(new_door, door, last_counter, new_counter, key_layout, world, player):
+#                 last_counter = new_counter
+#                 opened_doors = proposed_doors
+#                 bk_opened = bk_open
+#             else:
+#                 ignored_doors.add(new_door)
+#     return last_counter
+
+
+def find_best_counter(door, key_layout, odd_counter, skip_bk, empty_flag):
+    best, best_ctr, locations = 0, None, 0
+    for code, counter in key_layout.key_counters.items():
+        if door not in counter.open_doors:
+            if best_ctr is None or counter.used_keys > best or (counter.used_keys == best and count_locations(counter) > locations):
+                if not skip_bk or not counter.big_key_opened:
+                    if empty_flag or not relative_empty_counter(odd_counter, counter):
+                        best = counter.used_keys
+                        best_ctr = counter
+                        locations = count_locations(counter)
+    return best_ctr
+
+
+def count_locations(ctr):
+    return len(ctr.free_locations) + len(ctr.key_only_locations) + len(ctr.other_locations) + len(ctr.important_locations)
 
 
 def find_worst_counter(door, odd_counter, key_counter, key_layout, skip_bk):  # try to waste as many keys as possible?
@@ -638,7 +717,7 @@ def find_worst_counter(door, odd_counter, key_counter, key_layout, skip_bk):  #
         for new_door in door_set:
             proposed_doors = {**opened_doors, **dict.fromkeys([new_door, new_door.dest])}
             bk_open = bk_opened or new_door.bigKey
-            new_counter = find_counter(proposed_doors, bk_open, key_layout)
+            new_counter = find_counter(proposed_doors, bk_open, key_layout, key_counter.prize_doors_opened)
             bk_open = new_counter.big_key_opened
             if not new_door.bigKey and progressive_ctr(new_counter, last_counter) and relative_empty_counter_2(odd_counter, new_counter):
                 ignored_doors.add(new_door)
@@ -690,7 +769,7 @@ def key_wasted(new_door, old_door, old_counter, new_counter, key_layout, world,
         for new_child in new_children:
             proposed_doors = {**opened_doors, **dict.fromkeys([new_child, new_child.dest])}
             bk_open = bk_opened or new_door.bigKey
-            new_counter = find_counter(proposed_doors, bk_open, key_layout)
+            new_counter = find_counter(proposed_doors, bk_open, key_layout, current_counter.prize_doors_opened)
             if key_wasted(new_child, old_door, current_counter, new_counter, key_layout, world, player):
                 wasted_keys += 1
             if new_avail - wasted_keys < old_avail:
@@ -698,10 +777,11 @@ def key_wasted(new_door, old_door, old_counter, new_counter, key_layout, world,
     return False
 
 
-def find_next_counter(new_door, old_counter, key_layout):
+def find_next_counter(new_door, old_counter, key_layout, prize_flag=None):
     proposed_doors = {**old_counter.open_doors, **dict.fromkeys([new_door, new_door.dest])}
     bk_open = old_counter.big_key_opened or new_door.bigKey
-    return find_counter(proposed_doors, bk_open, key_layout)
+    prize_flag = prize_flag if prize_flag else old_counter.prize_doors_opened
+    return find_counter(proposed_doors, bk_open, key_layout, prize_flag)
 
 
 def check_special_locations(locations):
@@ -717,7 +797,7 @@ def calc_avail_keys(key_counter, world, player):
     return raw_avail - key_counter.used_keys
 
 
-def create_rule(key_counter, prev_counter, key_layout, world, player):
+def create_rule(key_counter, prev_counter, world, player):
     # prev_chest_keys = available_chest_small_keys(prev_counter, world)
     # prev_avail = prev_chest_keys + len(prev_counter.key_only_locations)
     chest_keys = available_chest_small_keys(key_counter, world, player)
@@ -736,6 +816,11 @@ def create_rule(key_counter, prev_counter, key_layout, world, player):
     return DoorRules(rule_num, is_valid)
 
 
+def create_worst_case_rule(rules, key_counter, world, player):
+    required_keys = key_counter.used_keys + 1  # this makes more sense, if key_counter has wasted all keys
+    rules.new_rules[KeyRuleType.WorstCase] = required_keys
+
+
 def check_for_self_lock_key(rule, door, parent_counter, key_layout, world, player):
     if world.accessibility[player] != 'locations':
         counter = find_inverted_counter(door, parent_counter, key_layout, world, player)
@@ -744,11 +829,12 @@ def check_for_self_lock_key(rule, door, parent_counter, key_layout, world, playe
         if len(counter.free_locations) == 1 and len(counter.key_only_locations) == 0 and not counter.important_location:
             rule.allow_small = True
             rule.small_location = next(iter(counter.free_locations))
+            rule.new_rules[KeyRuleType.AllowSmall] = rule.new_rules[KeyRuleType.WorstCase] - 1
 
 
 def find_inverted_counter(door, parent_counter, key_layout, world, player):
     # open all doors in counter
-    counter = open_all_counter(parent_counter, key_layout, door=door)
+    counter = open_all_counter(parent_counter, key_layout, world, player, door=door)
     max_counter = find_max_counter(key_layout)
     # find the difference
     inverted_counter = KeyCounter(key_layout.max_chests)
@@ -764,7 +850,7 @@ def find_inverted_counter(door, parent_counter, key_layout, world, player):
     return inverted_counter
 
 
-def open_all_counter(parent_counter, key_layout, door=None, skipBk=False):
+def open_all_counter(parent_counter, key_layout, world, player, door=None, skipBk=False):
     changed = True
     counter = parent_counter
     proposed_doors = dict.fromkeys(parent_counter.open_doors.keys())
@@ -776,14 +862,12 @@ def open_all_counter(parent_counter, key_layout, door=None, skipBk=False):
                 if skipBk:
                     if not child.bigKey:
                         doors_to_open[child] = None
-                elif not child.bigKey or not key_layout.big_key_special or counter.big_key_opened:
+                elif can_open_door_by_counter(child, counter, key_layout, world, player):
                     doors_to_open[child] = None
         if len(doors_to_open.keys()) > 0:
             proposed_doors = {**proposed_doors, **doors_to_open}
-            bk_hint = counter.big_key_opened
-            for d in doors_to_open.keys():
-                bk_hint = bk_hint or d.bigKey
-            counter = find_counter(proposed_doors, bk_hint, key_layout)
+            bk_hint = counter.big_key_opened or any(d.bigKey for d in doors_to_open.keys())
+            counter = find_counter(proposed_doors, bk_hint, key_layout, True)
             changed = True
     return counter
 
@@ -804,7 +888,7 @@ def open_some_counter(parent_counter, key_layout, ignored_doors):
             bk_hint = counter.big_key_opened
             for d in doors_to_open.keys():
                 bk_hint = bk_hint or d.bigKey
-            counter = find_counter(proposed_doors, bk_hint, key_layout)
+            counter = find_counter(proposed_doors, bk_hint, key_layout, parent_counter.prize_doors_opened)
             changed = True
     return counter
 
@@ -845,16 +929,16 @@ def big_key_drop_available(key_counter):
 def bk_restricted_rules(rule, door, odd_counter, empty_flag, key_counter, key_layout, world, player):
     if key_counter.big_key_opened:
         return
-    best_counter = find_best_counter(door, odd_counter, key_counter, key_layout, world, player, True, empty_flag)
-    bk_rule = create_rule(best_counter, key_counter, key_layout, world, player)
+    best_counter = find_best_counter(door, key_layout, odd_counter, True, empty_flag)
+    bk_rule = create_rule(best_counter, key_counter, world, player)
     if bk_rule.small_key_num >= rule.small_key_num:
         return
     door_open = find_next_counter(door, best_counter, key_layout)
     ignored_doors = dict_intersection(best_counter.child_doors, door_open.child_doors)
     dest_ignored = []
-    for door in ignored_doors.keys():
-        if door.dest not in ignored_doors:
-            dest_ignored.append(door.dest)
+    for d in ignored_doors.keys():
+        if d.dest not in ignored_doors:
+            dest_ignored.append(d.dest)
     ignored_doors = {**ignored_doors, **dict.fromkeys(dest_ignored)}
     post_counter = open_some_counter(door_open, key_layout, ignored_doors.keys())
     unique_loc = dict_difference(post_counter.free_locations, best_counter.free_locations)
@@ -862,8 +946,8 @@ def bk_restricted_rules(rule, door, odd_counter, empty_flag, key_counter, key_la
     if len(unique_loc) > 0:  # and bk_rule.is_valid
         rule.alternate_small_key = bk_rule.small_key_num
         rule.alternate_big_key_loc.update(unique_loc)
-    # elif not bk_rule.is_valid:
-    #     key_layout.key_logic.bk_restricted.update(unique_loc)
+        if not door.bigKey:
+            rule.new_rules[(KeyRuleType.Lock, key_layout.key_logic.bk_name)] = best_counter.used_keys + 1
 
 
 def find_worst_counter_wo_bk(small_key_num, accessible_set, door, odd_ctr, key_counter, key_layout):
@@ -887,12 +971,19 @@ def find_worst_counter_wo_bk(small_key_num, accessible_set, door, odd_ctr, key_c
     return worst_counter, post_counter, bk_rule_num
 
 
-def open_a_door(door, child_state, flat_proposal):
+def open_a_door(door, child_state, flat_proposal, world, player):
     if door.bigKey or door.name in special_big_key_doors:
         child_state.big_key_opened = True
         child_state.avail_doors.extend(child_state.big_doors)
         child_state.opened_doors.extend(set([d.door for d in child_state.big_doors]))
         child_state.big_doors.clear()
+    elif door in child_state.prize_door_set:
+        child_state.prize_doors_opened = True
+        for exp_door in child_state.prize_doors:
+            new_region = exp_door.door.entrance.parent_region
+            child_state.visit_region(new_region, key_checks=True)
+            child_state.add_all_doors_check_keys(new_region, flat_proposal, world, player)
+        child_state.prize_doors.clear()
     else:
         child_state.opened_doors.append(door)
         doors_to_open = [x for x in child_state.small_doors if x.door == door]
@@ -935,6 +1026,7 @@ def only_sm_doors(key_counter):
             return False
     return True
 
+
 # doesn't count dest doors
 def count_unique_small_doors(key_counter, proposal):
     cnt = 0
@@ -949,7 +1041,7 @@ def count_unique_small_doors(key_counter, proposal):
 
 
 def exist_relevant_big_doors(key_counter, key_layout):
-    bk_counter = find_counter(key_counter.open_doors, True, key_layout, False)
+    bk_counter = find_counter(key_counter.open_doors, True, key_layout, key_counter.prize_doors_opened, False)
     if bk_counter is not None:
         diff = dict_difference(bk_counter.free_locations, key_counter.free_locations)
         if len(diff) > 0:
@@ -982,14 +1074,6 @@ def filter_big_chest(locations):
     return [x for x in locations if '- Big Chest' not in x.name]
 
 
-def count_locations_exclude_logic(locations, key_logic):
-    cnt = 0
-    for loc in locations:
-        if not location_is_bk_locked(loc, key_logic) and not loc.forced_item and not prize_or_event(loc):
-            cnt += 1
-    return cnt
-
-
 def location_is_bk_locked(loc, key_logic):
     return loc in key_logic.bk_chests or loc in key_logic.bk_locked
 
@@ -998,18 +1082,36 @@ def prize_or_event(loc):
     return loc.name in dungeon_events or '- Prize' in loc.name or loc.name in ['Agahnim 1', 'Agahnim 2']
 
 
-def count_free_locations(state):
+def boss_unavail(loc, world, player):
+    # todo: ambrosia
+    # return world.bossdrops[player] == 'ambrosia' and "- Boss" in loc.name
+    return False
+
+
+def blind_boss_unavail(loc, state, world, player):
+    if loc.name == "Thieves' Town - Boss":
+        # todo: check attic
+        return (loc.parent_region.dungeon.boss.name == 'Blind' and
+                (not any(x for x in state.found_locations if x.name == 'Suspicious Maiden') or
+                 (world.get_region('Thieves Attic Window', player).dungeon.name == 'Thieves Town' and
+                  not any(x for x in state.found_locations if x.name == 'Attic Cracked Floor'))))
+    return False
+
+
+def count_free_locations(state, world, player):
     cnt = 0
     for loc in state.found_locations:
-        if not prize_or_event(loc) and not loc.forced_item:
+        if (not prize_or_event(loc) and not loc.forced_item and not boss_unavail(loc, world, player)
+           and not blind_boss_unavail(loc, state, world, player)):
             cnt += 1
     return cnt
 
 
-def count_locations_exclude_big_chest(state):
+def count_locations_exclude_big_chest(state, world, player):
     cnt = 0
     for loc in state.found_locations:
-        if '- Big Chest' not in loc.name and not loc.forced_item and not prize_or_event(loc):
+        if ('- Big Chest' not in loc.name and not loc.forced_item and not boss_unavail(loc, world, player)
+           and not prize_or_event(loc) and not blind_boss_unavail(loc, state, world, player)):
             cnt += 1
     return cnt
 
@@ -1197,7 +1299,7 @@ def check_rules_deep(original_counter, key_layout, world, player):
             elif not door.bigKey:
                 can_open = True
             if can_open:
-                can_progress = smalls_opened or not big_maybe_not_found
+                can_progress = (big_avail or not big_maybe_not_found) if door.bigKey else smalls_opened
                 next_counter = find_next_counter(door, counter, key_layout)
                 c_id = cid(next_counter, key_layout)
                 if c_id not in completed:
@@ -1265,6 +1367,13 @@ def check_bk_special(regions, world, player):
     return False
 
 
+def forced_big_key_avail(locations):
+    for loc in locations:
+        if loc.forced_big_key():
+            return loc
+    return None
+
+
 # Soft lock stuff
 def validate_key_layout(key_layout, world, player):
     # retro is all good - except for hyrule castle in standard mode
@@ -1275,8 +1384,16 @@ def validate_key_layout(key_layout, world, player):
     state.key_locations = key_layout.max_chests
     state.big_key_special = check_bk_special(key_layout.sector.regions, world, player)
     for region in key_layout.start_regions:
-        state.visit_region(region, key_checks=True)
-        state.add_all_doors_check_keys(region, flat_proposal, world, player)
+        dungeon_entrance, portal_door = find_outside_connection(region)
+        if (len(key_layout.start_regions) > 1 and dungeon_entrance and
+           dungeon_entrance.name in ['Ganons Tower', 'Inverted Ganons Tower', 'Pyramid Fairy']
+           and key_layout.key_logic.dungeon in dungeon_prize):
+            state.append_door_to_list(portal_door, state.prize_doors)
+            state.prize_door_set[portal_door] = dungeon_entrance
+            key_layout.prize_relevant = True
+        else:
+            state.visit_region(region, key_checks=True)
+            state.add_all_doors_check_keys(region, flat_proposal, world, player)
     return validate_key_layout_sub_loop(key_layout, state, {}, flat_proposal, None, 0, world, player)
 
 
@@ -1287,7 +1404,10 @@ def validate_key_layout_sub_loop(key_layout, state, checked_states, flat_proposa
     if not smalls_avail and num_bigs == 0:
         return True   # I think that's the end
     # todo: fix state to separate out these types
-    ttl_locations = count_free_locations(state) if state.big_key_opened else count_locations_exclude_big_chest(state)
+    if state.big_key_opened:
+        ttl_locations = count_free_locations(state, world, player)
+    else:
+        ttl_locations = count_locations_exclude_big_chest(state, world, player)
     ttl_small_key_only = count_small_key_only_locations(state)
     available_small_locations = cnt_avail_small_locations(ttl_locations, ttl_small_key_only, state, world, player)
     available_big_locations = cnt_avail_big_locations(ttl_locations, state, world, player)
@@ -1301,14 +1421,16 @@ def validate_key_layout_sub_loop(key_layout, state, checked_states, flat_proposa
     if smalls_done and bk_done:
         return False
     else:
+        # todo: pretty sure you should OR these paths together, maybe when there's one location and it can
+        # either be small or big key
         if smalls_avail and available_small_locations > 0:
             for exp_door in state.small_doors:
                 state_copy = state.copy()
-                open_a_door(exp_door.door, state_copy, flat_proposal)
+                open_a_door(exp_door.door, state_copy, flat_proposal, world, player)
                 state_copy.used_smalls += 1
                 if state_copy.used_smalls > ttl_small_key_only:
                     state_copy.used_locations += 1
-                code = state_id(state_copy, flat_proposal)
+                code = validate_id(state_copy, flat_proposal)
                 if code not in checked_states.keys():
                     valid = validate_key_layout_sub_loop(key_layout, state_copy, checked_states, flat_proposal,
                                                          state, available_small_locations, world, player)
@@ -1319,10 +1441,23 @@ def validate_key_layout_sub_loop(key_layout, state, checked_states, flat_proposa
                     return False
         if not state.big_key_opened and (available_big_locations >= num_bigs > 0 or (found_forced_bk and num_bigs > 0)):
             state_copy = state.copy()
-            open_a_door(state.big_doors[0].door, state_copy, flat_proposal)
+            open_a_door(state.big_doors[0].door, state_copy, flat_proposal, world, player)
             if not found_forced_bk:
                 state_copy.used_locations += 1
-            code = state_id(state_copy, flat_proposal)
+            code = validate_id(state_copy, flat_proposal)
+            if code not in checked_states.keys():
+                valid = validate_key_layout_sub_loop(key_layout, state_copy, checked_states, flat_proposal,
+                                                     state, available_small_locations, world, player)
+                checked_states[code] = valid
+            else:
+                valid = checked_states[code]
+            if not valid:
+                return False
+        # todo: feel like you only open these if the boss is available???
+        if not state.prize_doors_opened and key_layout.prize_relevant:
+            state_copy = state.copy()
+            open_a_door(next(iter(state_copy.prize_door_set)), state_copy, flat_proposal, world, player)
+            code = validate_id(state_copy, flat_proposal)
             if code not in checked_states.keys():
                 valid = validate_key_layout_sub_loop(key_layout, state_copy, checked_states, flat_proposal,
                                                      state, available_small_locations, world, player)
@@ -1341,7 +1476,7 @@ def invalid_self_locking_key(key_layout, state, prev_state, prev_avail, world, p
     state_copy = state.copy()
     while len(new_bk_doors) > 0:
         for door in new_bk_doors:
-            open_a_door(door.door, state_copy, key_layout.flat_prop)
+            open_a_door(door.door, state_copy, key_layout.flat_prop, world, player)
         new_bk_doors = set(state_copy.big_doors).difference(set(prev_state.big_doors))
     expand_key_state(state_copy, key_layout.flat_prop, world, player)
     new_locations = set(state_copy.found_locations).difference(set(prev_state.found_locations))
@@ -1373,30 +1508,55 @@ def cnt_avail_small_locations(free_locations, key_only, state, world, player):
     return state.key_locations - state.used_smalls
 
 
+def cnt_avail_small_locations_by_ctr(free_locations, counter, layout, world, player):
+    if not world.keyshuffle[player] and not world.retro[player]:
+        bk_adj = 1 if counter.big_key_opened and not layout.big_key_special else 0
+        avail_chest_keys = min(free_locations - bk_adj, layout.max_chests)
+        return max(0, avail_chest_keys + len(counter.key_only_locations) - counter.used_keys)
+    return layout.max_chests + len(counter.key_only_locations) - counter.used_keys
+
+
 def cnt_avail_big_locations(ttl_locations, state, world, player):
     if not world.bigkeyshuffle[player]:
         return max(0, ttl_locations - state.used_locations) if not state.big_key_special else 0
     return 1 if not state.big_key_special else 0
 
 
+def cnt_avail_big_locations_by_ctr(ttl_locations, counter, layout, world, player):
+    if not world.bigkeyshuffle[player]:
+        bk_adj = 1 if counter.big_key_opened and not layout.big_key_special else 0
+        used_locations = max(0, counter.used_keys - len(counter.key_only_locations)) + bk_adj
+        return max(0, ttl_locations - used_locations) if not layout.big_key_special else 0
+    return 1 if not layout.big_key_special else 0
+
+
 def create_key_counters(key_layout, world, player):
     key_counters = {}
+    key_layout.found_doors.clear()
     flat_proposal = key_layout.flat_prop
     state = ExplorationState(dungeon=key_layout.sector.name)
     if world.doorShuffle[player] == 'vanilla':
-        state.key_locations = default_key_counts[key_layout.sector.name]
+        builder = world.dungeon_layouts[player][key_layout.sector.name]
+        state.key_locations = len(builder.key_door_proposal) - builder.key_drop_cnt
     else:
         builder = world.dungeon_layouts[player][key_layout.sector.name]
         state.key_locations = builder.total_keys - builder.key_drop_cnt
-    state.big_key_special, special_region = False, None
+    state.big_key_special = False
     for region in key_layout.sector.regions:
         for location in region.locations:
             if location.forced_big_key():
                 state.big_key_special = True
-                special_region = region
     for region in key_layout.start_regions:
-        state.visit_region(region, key_checks=True)
-        state.add_all_doors_check_keys(region, flat_proposal, world, player)
+        dungeon_entrance, portal_door = find_outside_connection(region)
+        if (len(key_layout.start_regions) > 1 and dungeon_entrance and
+           dungeon_entrance.name in ['Ganons Tower', 'Inverted Ganons Tower', 'Pyramid Fairy']
+           and key_layout.key_logic.dungeon in dungeon_prize):
+            state.append_door_to_list(portal_door, state.prize_doors)
+            state.prize_door_set[portal_door] = dungeon_entrance
+            key_layout.prize_relevant = True
+        else:
+            state.visit_region(region, key_checks=True)
+            state.add_all_doors_check_keys(region, flat_proposal, world, player)
     expand_key_state(state, flat_proposal, world, player)
     code = state_id(state, key_layout.flat_prop)
     key_counters[code] = create_key_counter(state, key_layout, world, player)
@@ -1404,12 +1564,15 @@ def create_key_counters(key_layout, world, player):
     while len(queue) > 0:
         next_key_counter, parent_state = queue.popleft()
         for door in next_key_counter.child_doors:
+            key_layout.found_doors.add(door)
+            if door.dest in flat_proposal and door.type != DoorType.SpiralStairs:
+                key_layout.found_doors.add(door.dest)
             child_state = parent_state.copy()
             if door.bigKey or door.name in special_big_key_doors:
                 key_layout.key_logic.bk_doors.add(door)
             # open the door, if possible
-            if not door.bigKey or not child_state.big_key_special or child_state.visited_at_all(special_region):
-                open_a_door(door, child_state, flat_proposal)
+            if can_open_door(door, child_state, world, player):
+                open_a_door(door, child_state, flat_proposal, world, player)
                 expand_key_state(child_state, flat_proposal, world, player)
                 code = state_id(child_state, key_layout.flat_prop)
                 if code not in key_counters.keys():
@@ -1419,9 +1582,52 @@ def create_key_counters(key_layout, world, player):
     return key_counters
 
 
+def find_outside_connection(region):
+    portal = next((x for x in region.entrances if ' Portal' in x.parent_region.name), None)
+    if portal:
+        dungeon_entrance = next(x for x in portal.parent_region.entrances
+                                if x.parent_region.type in [RegionType.LightWorld, RegionType.DarkWorld])
+        portal_entrance = next(x for x in portal.parent_region.entrances if x.parent_region == region)
+        return dungeon_entrance, portal_entrance.door
+    return None, None
+
+
+def can_open_door(door, state, world, player):
+    if state.big_key_opened:
+        ttl_locations = count_free_locations(state, world, player)
+    else:
+        ttl_locations = count_locations_exclude_big_chest(state, world, player)
+    if door.smallKey:
+        ttl_small_key_only = count_small_key_only_locations(state)
+        available_small_locations = cnt_avail_small_locations(ttl_locations, ttl_small_key_only, state, world, player)
+        return available_small_locations > 0
+    elif door.bigKey:
+        available_big_locations = cnt_avail_big_locations(ttl_locations, state, world, player)
+        found_forced_bk = state.found_forced_bk()
+        return not state.big_key_opened and (available_big_locations > 0 or found_forced_bk)
+    else:
+        return True
+
+
+def can_open_door_by_counter(door, counter: KeyCounter, layout, world, player):
+    if counter.big_key_opened:
+        ttl_locations = len(counter.free_locations)
+    else:
+        ttl_locations = len([x for x in counter.free_locations if '- Big Chest' not in x.name])
+
+    if door.smallKey:
+        # ttl_small_key_only = len(counter.key_only_locations)
+        return cnt_avail_small_locations_by_ctr(ttl_locations, counter, layout, world, player) > 0
+    elif door.bigKey:
+        available_big_locations = cnt_avail_big_locations_by_ctr(ttl_locations, counter, layout, world, player)
+        return not counter.big_key_opened and available_big_locations > 0 and not layout.big_key_special
+    else:
+        return True
+
+
 def create_key_counter(state, key_layout, world, player):
     key_counter = KeyCounter(key_layout.max_chests)
-    key_counter.child_doors.update(dict.fromkeys(unique_doors(state.small_doors+state.big_doors)))
+    key_counter.child_doors.update(dict.fromkeys(unique_doors(state.small_doors+state.big_doors+state.prize_doors)))
     for loc in state.found_locations:
         if important_location(loc, world, player):
             key_counter.important_location = True
@@ -1438,6 +1644,10 @@ def create_key_counter(state, key_layout, world, player):
     key_counter.open_doors.update(dict.fromkeys(state.opened_doors))
     key_counter.used_keys = count_unique_sm_doors(state.opened_doors)
     key_counter.big_key_opened = state.big_key_opened
+    if len(state.prize_door_set) > 0 and state.prize_doors_opened:
+        key_counter.prize_doors_opened = True
+    if any(x for x in key_counter.important_locations if '- Prize' in x.name):
+        key_counter.prize_received = True
     return key_counter
 
 
@@ -1488,11 +1698,23 @@ def state_id(state, flat_proposal):
     s_id = '1' if state.big_key_opened else '0'
     for d in flat_proposal:
         s_id += '1' if d in state.opened_doors else '0'
+    if len(state.prize_door_set) > 0:
+        s_id += '1' if state.prize_doors_opened else '0'
     return s_id
 
 
-def find_counter(opened_doors, bk_hint, key_layout, raise_on_error=True):
-    counter = find_counter_hint(opened_doors, bk_hint, key_layout)
+def validate_id(state, flat_proposal):
+    s_id = '1' if state.big_key_opened else '0'
+    for d in flat_proposal:
+        s_id += '1' if d in state.opened_doors else '0'
+    if len(state.prize_door_set) > 0:
+        s_id += '1' if state.prize_doors_opened else '0'
+    s_id += str(state.used_locations)
+    return s_id
+
+
+def find_counter(opened_doors, bk_hint, key_layout, prize_flag, raise_on_error=True):
+    counter = find_counter_hint(opened_doors, bk_hint, key_layout, prize_flag)
     if counter is not None:
         return counter
     more_doors = []
@@ -1501,43 +1723,47 @@ def find_counter(opened_doors, bk_hint, key_layout, raise_on_error=True):
         if door.dest not in opened_doors.keys():
             more_doors.append(door.dest)
     if len(more_doors) > len(opened_doors.keys()):
-        counter = find_counter_hint(dict.fromkeys(more_doors), bk_hint, key_layout)
+        counter = find_counter_hint(dict.fromkeys(more_doors), bk_hint, key_layout, prize_flag)
         if counter is not None:
             return counter
     if raise_on_error:
-        raise Exception('Unable to find door permutation. Init CID: %s' % counter_id(opened_doors, bk_hint, key_layout.flat_prop))
+        cid = counter_id(opened_doors, bk_hint, key_layout.flat_prop, key_layout.prize_relevant, prize_flag)
+        raise Exception(f'Unable to find door permutation. Init CID: {cid}')
     return None
 
 
-def find_counter_hint(opened_doors, bk_hint, key_layout):
-    cid = counter_id(opened_doors, bk_hint, key_layout.flat_prop)
+def find_counter_hint(opened_doors, bk_hint, key_layout, prize_flag):
+    cid = counter_id(opened_doors, bk_hint, key_layout.flat_prop, key_layout.prize_relevant, prize_flag)
     if cid in key_layout.key_counters.keys():
         return key_layout.key_counters[cid]
     if not bk_hint:
-        cid = counter_id(opened_doors, True, key_layout.flat_prop)
+        cid = counter_id(opened_doors, True, key_layout.flat_prop, key_layout.prize_relevant, prize_flag)
         if cid in key_layout.key_counters.keys():
             return key_layout.key_counters[cid]
     return None
 
 
 def find_max_counter(key_layout):
-    max_counter = find_counter_hint(dict.fromkeys(key_layout.flat_prop), False, key_layout)
+    max_counter = find_counter_hint(dict.fromkeys(key_layout.found_doors), False, key_layout, True)
     if max_counter is None:
         raise Exception("Max Counter is none - something is amiss")
     if len(max_counter.child_doors) > 0:
-        max_counter = find_counter_hint(dict.fromkeys(key_layout.flat_prop), True, key_layout)
+        max_counter = find_counter_hint(dict.fromkeys(key_layout.found_doors), True, key_layout, True)
     return max_counter
 
 
-def counter_id(opened_doors, bk_unlocked, flat_proposal):
+def counter_id(opened_doors, bk_unlocked, flat_proposal, prize_relevant, prize_flag):
     s_id = '1' if bk_unlocked else '0'
     for d in flat_proposal:
         s_id += '1' if d in opened_doors.keys() else '0'
+    if prize_relevant:
+        s_id += '1' if prize_flag else '0'
     return s_id
 
 
 def cid(counter, key_layout):
-    return counter_id(counter.open_doors, counter.big_key_opened, key_layout.flat_prop)
+    return counter_id(counter.open_doors, counter.big_key_opened, key_layout.flat_prop,
+                      key_layout.prize_relevant, counter.prize_doors_opened)
 
 
 # class SoftLockException(Exception):
@@ -1747,8 +1973,18 @@ def validate_key_placement(key_layout, world, player):
         found_locations = set(i for i in counter.free_locations if big_found or "- Big Chest" not in i.name)
         found_keys = sum(1 for i in found_locations if i.item is not None and i.item.name == smallkey_name and i.item.player == player) + \
                      len(counter.key_only_locations) + keys_outside
+        if key_layout.prize_relevant:
+            found_prize = any(x for x in counter.important_locations if '- Prize' in x.name)
+            if not found_prize and key_layout.sector.name in dungeon_prize:
+                prize_loc = world.get_location(dungeon_prize[key_layout.sector.name], player)
+                # todo: pyramid fairy only care about crystals 5 & 6
+                found_prize = 'Crystal' not in prize_loc.item.name
+        else:
+            found_prize = False
         can_progress = (not counter.big_key_opened and big_found and any(d.bigKey for d in counter.child_doors)) or \
-                       found_keys > counter.used_keys and any(not d.bigKey for d in counter.child_doors)
+            found_keys > counter.used_keys and any(not d.bigKey for d in counter.child_doors) or \
+            self_locked_child_door(key_layout, counter) or \
+            (key_layout.prize_relevant and not counter.prize_doors_opened and found_prize)
         if not can_progress:
             missing_locations = set(max_counter.free_locations.keys()).difference(found_locations)
             missing_items = [l for l in missing_locations if l.item is None or (l.item.name != smallkey_name and l.item.name != bigkey_name) or "- Boss" in l.name]
@@ -1762,3 +1998,11 @@ def validate_key_placement(key_layout, world, player):
 
     return True
 
+
+def self_locked_child_door(key_layout, counter):
+    if len(counter.child_doors) == 1:
+        door = next(iter(counter.child_doors.keys()))
+        return door.smallKey and key_layout.key_logic.door_rules[door.name].allow_small
+    return False
+
+
diff --git a/Main.py b/Main.py
index de05313c..ee9e83fb 100644
--- a/Main.py
+++ b/Main.py
@@ -28,7 +28,7 @@ from Fill import sell_potions, sell_keys, balance_multiworld_progression, balanc
 from ItemList import generate_itempool, difficulties, fill_prizes, customize_shops
 from Utils import output_path, parse_player_names
 
-__version__ = '0.5.0.3-u'
+__version__ = '0.5.1.0-u'
 
 from source.classes.BabelFish import BabelFish
 
@@ -244,7 +244,7 @@ def main(args, seed=None, fish=None):
         balance_multiworld_progression(world)
 
     # if we only check for beatable, we can do this sanity check first before creating the rom
-    if not world.can_beat_game():
+    if not world.can_beat_game(log_error=True):
         raise RuntimeError(world.fish.translate("cli","cli","cannot.beat.game"))
 
     for player in range(1, world.players+1):
@@ -402,6 +402,8 @@ def copy_world(world):
     ret.mixed_travel = world.mixed_travel.copy()
     ret.standardize_palettes = world.standardize_palettes.copy()
 
+    ret.exp_cache = world.exp_cache.copy()
+
     for player in range(1, world.players + 1):
         if world.mode[player] != 'inverted':
             create_regions(ret, player)
@@ -461,6 +463,7 @@ def copy_world(world):
         # these need to be modified properly by set_rules
         new_location.access_rule = lambda state: True
         new_location.item_rule = lambda state: True
+        new_location.forced_item = location.forced_item
 
     # copy remaining itempool. No item in itempool should have an assigned location
     for item in world.itempool:
@@ -538,11 +541,11 @@ def create_playthrough(world):
     while sphere_candidates:
         state.sweep_for_events(key_only=True)
 
-        sphere = []
+        sphere = set()
         # build up spheres of collection radius. Everything in each sphere is independent from each other in dependencies and only depends on lower spheres
         for location in sphere_candidates:
             if state.can_reach(location) and state.not_flooding_a_key(world, location):
-                sphere.append(location)
+                sphere.add(location)
 
         for location in sphere:
             sphere_candidates.remove(location)
@@ -563,21 +566,24 @@ def create_playthrough(world):
 
     # in the second phase, we cull each sphere such that the game is still beatable, reducing each range of influence to the bare minimum required inside it
     for num, sphere in reversed(list(enumerate(collection_spheres))):
-        to_delete = []
+        to_delete = set()
         for location in sphere:
             # we remove the item at location and check if game is still beatable
             logging.getLogger('').debug('Checking if %s (Player %d) is required to beat the game.', location.item.name, location.item.player)
             old_item = location.item
             location.item = None
+            # todo: this is not very efficient, but I'm not sure how else to do it for this backwards logic
+            # world.clear_exp_cache()
             if world.can_beat_game(state_cache[num]):
-                to_delete.append(location)
+                # logging.getLogger('').debug(f'{old_item.name} (Player {old_item.player}) is not required')
+                to_delete.add(location)
             else:
                 # still required, got to keep it around
+                # logging.getLogger('').debug(f'{old_item.name} (Player {old_item.player}) is required')
                 location.item = old_item
 
         # cull entries in spheres for spoiler walkthrough at end
-        for location in to_delete:
-            sphere.remove(location)
+        sphere -= to_delete
 
     # second phase, sphere 0
     for item in [i for i in world.precollected_items if i.advancement]:
@@ -593,7 +599,7 @@ def create_playthrough(world):
     # used to access it was deemed not required.) So we need to do one final sphere collection pass
     # to build up the correct spheres
 
-    required_locations = [item for sphere in collection_spheres for item in sphere]
+    required_locations = {item for sphere in collection_spheres for item in sphere}
     state = CollectionState(world)
     collection_spheres = []
     while required_locations:
@@ -609,7 +615,10 @@ def create_playthrough(world):
 
         logging.getLogger('').debug(world.fish.translate("cli","cli","building.final.spheres"), len(collection_spheres), len(sphere), len(required_locations))
         if not sphere:
-            raise RuntimeError(world.fish.translate("cli","cli","cannot.reach.required"))
+            if world.has_beaten_game(state):
+                required_locations.clear()
+            else:
+                raise RuntimeError(world.fish.translate("cli","cli","cannot.reach.required"))
 
     # store the required locations for statistical analysis
     old_world.required_locations = [(location.name, location.player) for sphere in collection_spheres for location in sphere]
@@ -630,7 +639,7 @@ def create_playthrough(world):
     old_world.spoiler.paths = dict()
     for player in range(1, world.players + 1):
         old_world.spoiler.paths.update({location.gen_name(): get_path(state, location.parent_region) for sphere in collection_spheres for location in sphere if location.player == player})
-        for _, path in dict(old_world.spoiler.paths).items():
+        for path in dict(old_world.spoiler.paths).values():
             if any(exit == 'Pyramid Fairy' for (_, exit) in path):
                 if world.mode[player] != 'inverted':
                     old_world.spoiler.paths[str(world.get_region('Big Bomb Shop', player))] = get_path(state, world.get_region('Big Bomb Shop', player))
@@ -638,6 +647,6 @@ def create_playthrough(world):
                     old_world.spoiler.paths[str(world.get_region('Inverted Big Bomb Shop', player))] = get_path(state, world.get_region('Inverted Big Bomb Shop', player))
 
     # we can finally output our playthrough
-    old_world.spoiler.playthrough = OrderedDict([("0", [str(item) for item in world.precollected_items if item.advancement])])
+    old_world.spoiler.playthrough = {"0": [str(item) for item in world.precollected_items if item.advancement]}
     for i, sphere in enumerate(collection_spheres):
         old_world.spoiler.playthrough[str(i + 1)] = {location.gen_name(): str(location.item) for location in sphere}
diff --git a/Mystery.py b/Mystery.py
index a3948b6e..73644500 100644
--- a/Mystery.py
+++ b/Mystery.py
@@ -31,6 +31,7 @@ def main():
     parser.add_argument('--rom')
     parser.add_argument('--enemizercli')
     parser.add_argument('--outputpath')
+    parser.add_argument('--loglevel', default='info', choices=['debug', 'info', 'warning', 'error', 'critical'])
     for player in range(1, multiargs.multi + 1):
         parser.add_argument(f'--p{player}', help=argparse.SUPPRESS)
     args = parser.parse_args()
@@ -63,6 +64,7 @@ def main():
     erargs.race = True
     erargs.outputname = seedname
     erargs.outputpath = args.outputpath
+    erargs.loglevel = args.loglevel
 
     if args.rom:
         erargs.rom = args.rom
diff --git a/Rom.py b/Rom.py
index 063cab58..d39675db 100644
--- a/Rom.py
+++ b/Rom.py
@@ -102,8 +102,7 @@ class LocalRom(object):
         self.buffer[address] = value
 
     def write_bytes(self, startaddress, values):
-        for i, value in enumerate(values):
-            self.write_byte(startaddress + i, value)
+        self.buffer[startaddress:startaddress + len(values)] = values
 
     def write_to_file(self, file):
         with open(file, 'wb') as outfile:
@@ -2796,7 +2795,7 @@ def write_pots_to_rom(rom, pot_contents):
             pots = [pot for pot in pot_contents[i] if pot.item != PotItem.Nothing]
             if len(pots) > 0:
                 write_int16(rom, pot_item_room_table_lookup + 2*i, n)
-                rom.write_bytes(n, itertools.chain(*((pot.x,pot.y,pot.item) for pot in pots)))
+                rom.write_bytes(n, list(itertools.chain.from_iterable(((pot.x, pot.y, pot.item) for pot in pots))))
                 n += 3*len(pots) + 2
                 rom.write_bytes(n - 2, [0xFF,0xFF])
             else:
diff --git a/Rules.py b/Rules.py
index 23a15f67..28d627da 100644
--- a/Rules.py
+++ b/Rules.py
@@ -3,7 +3,7 @@ import logging
 from collections import deque
 
 import OverworldGlitchRules
-from BaseClasses import CollectionState, RegionType, DoorType, Entrance, CrystalBarrier
+from BaseClasses import CollectionState, RegionType, DoorType, Entrance, CrystalBarrier, KeyRuleType
 from RoomData import DoorKind
 from OverworldGlitchRules import overworld_glitches_rules
 
@@ -1941,14 +1941,8 @@ bunny_impassible_doors = {
 def add_key_logic_rules(world, player):
     key_logic = world.key_logic[player]
     for d_name, d_logic in key_logic.items():
-        for door_name, keys in d_logic.door_rules.items():
-            spot = world.get_entrance(door_name, player)
-            if not world.retro[player] or world.mode[player] != 'standard' or not retro_in_hc(spot):
-                rule = create_advanced_key_rule(d_logic, player, keys)
-                if keys.opposite:
-                    rule = or_rule(rule, create_advanced_key_rule(d_logic, player, keys.opposite))
-                add_rule(spot, rule)
-
+        for door_name, rule in d_logic.door_rules.items():
+            add_rule(world.get_entrance(door_name, player), eval_small_key_door(door_name, d_name, player))
         for location in d_logic.bk_restricted:
             if not location.forced_item:
                 forbid_item(location, d_logic.bk_name, player)
@@ -1956,8 +1950,9 @@ def add_key_logic_rules(world, player):
             forbid_item(location, d_logic.small_key_name, player)
         for door in d_logic.bk_doors:
             add_rule(world.get_entrance(door.name, player), create_rule(d_logic.bk_name, player))
-        for chest in d_logic.bk_chests:
-            add_rule(world.get_location(chest.name, player), create_rule(d_logic.bk_name, player))
+        if len(d_logic.bk_doors) > 0 or len(d_logic.bk_chests) > 1:
+            for chest in d_logic.bk_chests:
+                add_rule(world.get_location(chest.name, player), create_rule(d_logic.bk_name, player))
     if world.retro[player]:
         for d_name, layout in world.key_layout[player].items():
             for door in layout.flat_prop:
@@ -1965,6 +1960,36 @@ def add_key_logic_rules(world, player):
                     add_rule(door.entrance, create_key_rule('Small Key (Universal)', player, 1))
 
 
+def eval_small_key_door_main(state, door_name, dungeon, player):
+    if state.is_door_open(door_name, player):
+        return True
+    key_logic = state.world.key_logic[player][dungeon]
+    door_rule = key_logic.door_rules[door_name]
+    door_openable = False
+    for ruleType, number in door_rule.new_rules.items():
+        if door_openable:
+            return True
+        if ruleType == KeyRuleType.WorstCase:
+            door_openable |= state.has_sm_key(key_logic.small_key_name, player, number)
+        elif ruleType == KeyRuleType.AllowSmall:
+            if (door_rule.small_location.item and door_rule.small_location.item.name == key_logic.small_key_name
+               and door_rule.small_location.item.player == player):
+                return True  # always okay if allow small is on
+        elif isinstance(ruleType, tuple):
+            lock, lock_item = ruleType
+            # this doesn't track logical locks yet, i.e. hammer locks the item and hammer is there, but the item isn't
+            for loc in door_rule.alternate_big_key_loc:
+                spot = state.world.get_location(loc, player)
+                if spot.item and spot.item.name == lock_item:
+                    door_openable |= state.has_sm_key(key_logic.small_key_name, player, number)
+                    break
+    return door_openable
+
+
+def eval_small_key_door(door_name, dungeon, player):
+    return lambda state: eval_small_key_door_main(state, door_name, dungeon, player)
+
+
 def retro_in_hc(spot):
     return spot.parent_region.dungeon.name == 'Hyrule Castle' if spot.parent_region.dungeon else False
 
diff --git a/Utils.py b/Utils.py
index cf3db3fb..b8cf5497 100644
--- a/Utils.py
+++ b/Utils.py
@@ -1,10 +1,12 @@
 #!/usr/bin/env python3
 import os
 import re
+import operator as op
 import subprocess
 import sys
 import xml.etree.ElementTree as ET
 from collections import defaultdict
+from functools import reduce
 
 
 def int16_as_bytes(value):
@@ -116,6 +118,28 @@ def make_new_base2current(old_rom='Zelda no Densetsu - Kamigami no Triforce (Jap
     return "New Rom Hash: " + basemd5.hexdigest()
 
 
+def kth_combination(k, l, r):
+    if r == 0:
+        return []
+    elif len(l) == r:
+        return l
+    else:
+        i = ncr(len(l)-1, r-1)
+        if k < i:
+            return l[0:1] + kth_combination(k, l[1:], r-1)
+        else:
+            return kth_combination(k-i, l[1:], r)
+
+
+def ncr(n, r):
+    if r == 0:
+        return 1
+    r = min(r, n-r)
+    numerator = reduce(op.mul, range(n, n-r, -1), 1)
+    denominator = reduce(op.mul, range(1, r+1), 1)
+    return numerator / denominator
+
+
 entrance_offsets = {
     'Sanctuary': 0x2,
     'HC West': 0x3,
diff --git a/resources/app/cli/lang/en.json b/resources/app/cli/lang/en.json
index 3ace31f7..67efab1d 100644
--- a/resources/app/cli/lang/en.json
+++ b/resources/app/cli/lang/en.json
@@ -2,7 +2,7 @@
   "cli": {
     "yes": "Yes",
     "no": "No",
-    "app.title": "ALttP Door Randomizer Version %s - Seed: %s, Code: %s",
+    "app.title": "ALttP Door Randomizer Version %s : --seed %s --code %s",
     "version": "Version",
     "seed": "Seed",
     "player": "Player",