diff --git a/src/game.rs b/src/game.rs
index 497e6d6..aaebc13 100644
--- a/src/game.rs
+++ b/src/game.rs
@@ -346,7 +346,7 @@ impl Game {
         let mut sprite_id_changes:   HashMap<String, String> = HashMap::new();
 
         fn insert_if_different(map: &mut HashMap<String, String>, old: String, new: String) {
-            if old != new {
+            if old != new && ! map.contains_key(&old) {
                 map.insert(old, new);
             }
         }
@@ -418,8 +418,9 @@ impl Game {
 
             if item.dialogue_id.is_some() {
                 let key = item.dialogue_id.clone().unwrap();
-                if dialogue_id_changes.contains_key(&key) {
-                    item.dialogue_id = Some(dialogue_id_changes[&key].clone());
+                let change = dialogue_id_changes.get(&key);
+                if change.is_some() {
+                    item.dialogue_id = Some(change.unwrap().clone());
                 }
             }
 
@@ -442,8 +443,9 @@ impl Game {
         for room in &game.rooms {
             let mut room = room.clone();
 
-            if room_id_changes.contains_key(&room.id) {
-                room.id = room_id_changes.get(&room.id).unwrap().clone();
+            let room_id_change = room_id_changes.get(&room.id);
+            if room_id_change.is_some() {
+                room.id = room_id_change.unwrap().clone();
             }
 
             if room.palette_id.is_some()  {
@@ -955,5 +957,7 @@ 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));
+
+        
     }
 }