diff --git a/html/src/main/java/com/agifans/agile/gwt/GwtAgileRunner.java b/html/src/main/java/com/agifans/agile/gwt/GwtAgileRunner.java
index 10fff31..04f0558 100644
--- a/html/src/main/java/com/agifans/agile/gwt/GwtAgileRunner.java
+++ b/html/src/main/java/com/agifans/agile/gwt/GwtAgileRunner.java
@@ -33,15 +33,6 @@ public class GwtAgileRunner extends AgileRunner {
      */
     private Worker worker;
     
-    /**
-     * Indicates that the worker is currently executing the tick, i.e. a single interpretation 
-     * cycle. This flag exists because there are some AGI commands that wait for something to 
-     * happen before continuing. For example, a print window will stay up for a defined timeout
-     * period or until a key is pressed. In such cases, the thread can be performing a tick 
-     * for the duration of what would normally be many ticks. 
-     */
-    private boolean inTick;
-    
     /**
      * Holds a reference to the Audio HTML element that is playing the current sound, or null
      * if there is no sound being played. It is not possible in AGI to play two sounds at 
@@ -102,13 +93,6 @@ public void onMessage(MessageEvent event) {
                 JavaScriptObject eventObject = event.getDataAsObject();
                 
                 switch (getEventType(eventObject)) {
-                    case "TickComplete":
-                        // Allows the next tick to be triggered. We only allow one tick at
-                        // a time, otherwise the web worker would get a flood of Tick messages
-                        // when it is busy waiting for a key or similar.
-                        inTick = false;
-                        break;
-                        
                     case "QuitGame":
                         // This message is sent from the worker when the game has ended, usually
                         // due to the user quitting the game.
@@ -247,13 +231,9 @@ private void stopCurrentSound() {
     
     @Override
     public void animationTick() {
-        if (!inTick && (worker != null)) {
-            inTick = true;  // NOTE: Set to false by "TickComplete" message.
-            
-            // Send a message to the web worker to tell it to perform an animation tick, 
-            // but only if it isn't already in an animation tick.
-            worker.postObject("Tick", JavaScriptObject.createObject());
-        }
+        // Nothing to do for GWT version. The web worker triggers itself for animation
+        // ticks, using the total ticks that is set by UI thread to determine when to
+        // run.
     }
 
     @Override
@@ -264,7 +244,6 @@ public void stop() {
         stopCurrentSound();
         pixelData.clearState();
         variableData.clearState();
-        inTick = false;
         stopped = true;
     }
 
diff --git a/html/src/main/java/com/agifans/agile/worker/AgileWebWorker.java b/html/src/main/java/com/agifans/agile/worker/AgileWebWorker.java
index 82969eb..0ce1f9d 100644
--- a/html/src/main/java/com/agifans/agile/worker/AgileWebWorker.java
+++ b/html/src/main/java/com/agifans/agile/worker/AgileWebWorker.java
@@ -78,6 +78,11 @@ public class AgileWebWorker extends DedicatedWorkerEntryPoint implements Message
      */
     private OPFSGameFiles opfsGameFiles;
     
+    /**
+     * The total tick count at the time of the last animation tick.
+     */
+    private int lastTotalTickCount;
+    
     /**
      * Incoming messages from the UI thread are for two purposes: One is to set things 
      * up, and then once both sides are up and running, the UI thread then starts sending
@@ -122,18 +127,8 @@ public void onMessage(MessageEvent event) {
                 interpreter = new Interpreter(
                         game, userInput, wavePlayer, savedGameStore, 
                         pixelData, variableData);
-                break;
-                
-            case "Tick":
-                try {
-                    // Perform one animation tick.
-                    interpreter.animationTick();
-                    // Then notify the UI thread that the tick is complete.
-                    postObject("TickComplete", JavaScriptObject.createObject());
-                } catch (QuitAction qa) {
-                    // The user has quit the game, so notify the UI thread of this.
-                    postObject("QuitGame", JavaScriptObject.createObject());
-                }
+                lastTotalTickCount = variableData.getTotalTicks();
+                performAnimationTick(0);
                 break;
                 
             default:
@@ -141,6 +136,37 @@ public void onMessage(MessageEvent event) {
         }
     }
     
+    public void performAnimationTick(double timestamp) {
+        try {
+            int currentTotalTicks = variableData.getTotalTicks();
+            int numOfTicksToRun = (currentTotalTicks - this.lastTotalTickCount);
+            this.lastTotalTickCount = currentTotalTicks;
+            
+            // Catch up with ticks, if we are behind.
+            while ((numOfTicksToRun-- > 0) && (variableData.getTotalTicks() == currentTotalTicks)) {
+                // Perform one animation tick.
+                interpreter.animationTick();
+            }
+            
+            requestNextAnimationFrame();
+            
+        } catch (QuitAction qa) {
+            // The user has quit the game, so notify the UI thread of this.
+            postObject("QuitGame", JavaScriptObject.createObject());
+        }
+    }
+    
+    public native void exportPerformAnimationTick() /*-{
+        var that = this;
+        $self.performAnimationTick = $entry(function(timestamp) {
+          that.@com.agifans.agile.worker.AgileWebWorker::performAnimationTick(D)(timestamp);
+        });
+    }-*/;
+
+    private native void requestNextAnimationFrame()/*-{
+        $self.requestAnimationFrame($self.performAnimationTick);
+    }-*/;
+    
     private native String getEventType(JavaScriptObject obj)/*-{
         return obj.name;
     }-*/;
@@ -176,6 +202,8 @@ protected final void setOnMessage(MessageHandler messageHandler) {
     
     @Override
     public void onWorkerLoad() {
+        exportPerformAnimationTick();
+        
         this.scope = DedicatedWorkerGlobalScope.get();
         this.opfsGameFiles = new OPFSGameFiles();
         
@@ -183,4 +211,8 @@ public void onWorkerLoad() {
         
         this.setOnMessage(this);
     }
+    
+    private final native void logToJSConsole(String message)/*-{
+        console.log(message);
+    }-*/;
 }