diff --git a/BaseClasses.py b/BaseClasses.py
index 1a06ef6b..1de23bc1 100644
--- a/BaseClasses.py
+++ b/BaseClasses.py
@@ -559,7 +559,9 @@ class MultiWorld():
         else:
             return all((self.has_beaten_game(state, p) for p in range(1, self.players + 1)))
 
-    def can_beat_game(self, starting_state: Optional[CollectionState] = None) -> bool:
+    def can_beat_game(self,
+                      starting_state: Optional[CollectionState] = None,
+                      locations: Optional[Iterable[Location]] = None) -> bool:
         if starting_state:
             if self.has_beaten_game(starting_state):
                 return True
@@ -568,7 +570,9 @@ class MultiWorld():
             state = CollectionState(self)
             if self.has_beaten_game(state):
                 return True
-        prog_locations = {location for location in self.get_locations() if location.item
+
+        base_locations = self.get_locations() if locations is None else locations
+        prog_locations = {location for location in base_locations if location.item
                           and location.item.advancement and location not in state.locations_checked}
 
         while prog_locations:
@@ -1603,21 +1607,19 @@ class Spoiler:
 
         # 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
-        restore_later: Dict[Location, Item] = {}
+        required_locations = {location for sphere in collection_spheres for location in sphere}
         for num, sphere in reversed(tuple(enumerate(collection_spheres))):
             to_delete: Set[Location] = set()
             for location in sphere:
-                # we remove the item at location and check if game is still beatable
+                # we remove the location from required_locations to sweep from, and check if the game is still beatable
                 logging.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
-                if multiworld.can_beat_game(state_cache[num]):
+                required_locations.remove(location)
+                if multiworld.can_beat_game(state_cache[num], required_locations):
                     to_delete.add(location)
-                    restore_later[location] = old_item
                 else:
                     # still required, got to keep it around
-                    location.item = old_item
+                    required_locations.add(location)
 
             # cull entries in spheres for spoiler walkthrough at end
             sphere -= to_delete
@@ -1634,7 +1636,7 @@ class Spoiler:
                 logging.debug('Checking if %s (Player %d) is required to beat the game.', item.name, item.player)
                 precollected_items.remove(item)
                 multiworld.state.remove(item)
-                if not multiworld.can_beat_game():
+                if not multiworld.can_beat_game(multiworld.state, required_locations):
                     # Add the item back into `precollected_items` and collect it into `multiworld.state`.
                     multiworld.push_precollected(item)
                 else:
@@ -1676,9 +1678,6 @@ class Spoiler:
             self.create_paths(state, collection_spheres)
 
         # repair the multiworld again
-        for location, item in restore_later.items():
-            location.item = item
-
         for item in removed_precollected:
             multiworld.push_precollected(item)