diff --git a/extra/game-worlds/game-worlds.factor b/extra/game-worlds/game-worlds.factor
index 864bd28fc1..fa6b326fa9 100644
--- a/extra/game-worlds/game-worlds.factor
+++ b/extra/game-worlds/game-worlds.factor
@@ -1,14 +1,15 @@
-USING: accessors game-input game-loop kernel ui.gadgets
+USING: accessors game-input game-loop kernel math ui.gadgets
 ui.gadgets.worlds ui.gestures ;
 IN: game-worlds
 
 TUPLE: game-world < world
-    game-loop ;
+    game-loop
+    { tick-slice float initial: 0.0 } ;
 
 GENERIC: tick-length ( world -- millis )
 
 M: game-world draw*
-    nip draw-world ;
+    swap >>tick-slice draw-world ;
 
 M: game-world begin-world
     dup [ tick-length ] [ ] bi <game-loop> [ >>game-loop ] keep start-loop