diff --git a/src/simulator/api-gdext/src/lib.rs b/src/simulator/api-gdext/src/lib.rs
index e4fbebce..bc5a3a00 100644
--- a/src/simulator/api-gdext/src/lib.rs
+++ b/src/simulator/api-gdext/src/lib.rs
@@ -1930,6 +1930,8 @@ impl IRefCounted for GdGameState {
                 pending_formation_shapes: Default::default(),
                 pending_split_requests: Default::default(),
                 pending_auto_join_requests: Default::default(),
+                tile_improvements: Default::default(),
+                improvement_registry: Default::default(),
             },
             base,
         }