diff --git a/src/game.rs b/src/game.rs
index 3a54f00..23a02fe 100644
--- a/src/game.rs
+++ b/src/game.rs
@@ -763,6 +763,31 @@ impl Game {
         new_id
     }
 
+    pub fn dedupe_tiles(&mut self) {
+        let mut tiles_temp = self.tiles.clone();
+        let mut unique_tiles: Vec<Tile> = Vec::new();
+        let mut tile_id_changes: HashMap<String, String> = HashMap::new();
+
+        while tiles_temp.len() > 0 {
+            let tile = tiles_temp.pop().unwrap();
+
+            if tile == crate::mock::tile_background() {
+                tile_id_changes.insert(tile.id, "0".to_string());
+            } else if tiles_temp.contains(&tile) {
+                // todo get the ID of the first matching tile
+                //tile_id_changes.insert(tile.id, tiles_temp);
+            } else {
+                unique_tiles.push(tile);
+            }
+        }
+
+        for room in &mut self.rooms {
+            room.change_tile_ids(&tile_id_changes);
+        }
+
+        self.tiles = unique_tiles;
+    }
+
     #[inline]
     fn version_line(&self) -> String {
         if self.version.is_some() {
@@ -955,7 +980,15 @@ mod test {
         game_b.add_sprite(sprite);
         game_a.merge(game_b);
         assert_eq!(game_a.get_sprite_by_id("2".to_string()).unwrap().room_id, Some(room_id));
+    }
 
-        
+    #[test]
+    fn test_dedupe_tiles() {
+        let mut game = crate::mock::game_default();
+        game.add_tile(crate::mock::tile_default());
+        game.add_tile(crate::mock::tile_default());
+        game.add_tile(crate::mock::tile_background());
+        game.dedupe_tiles();
+        assert_eq!(game.tiles, vec![crate::mock::tile_default()]);
     }
 }