diff --git a/app/assets/javascripts/workers/worker_world.js b/app/assets/javascripts/workers/worker_world.js
index a1a5d455a..97fea2e1d 100644
--- a/app/assets/javascripts/workers/worker_world.js
+++ b/app/assets/javascripts/workers/worker_world.js
@@ -14,8 +14,8 @@ if (!Function.prototype.bind) {
       throw new TypeError("Function.prototype.bind (Shim) - target is not callable");
     }
 
-    var aArgs = Array.prototype.slice.call(arguments, 1), 
-        fToBind = this, 
+    var aArgs = Array.prototype.slice.call(arguments, 1),
+        fToBind = this,
         fNOP = function () {},
         fBound = function () {
           return fToBind.apply(this instanceof fNOP && oThis
@@ -223,7 +223,7 @@ self.retrieveValueFromFrame = function retrieveValueFromFrame(args) {
                     var flowStates = self.debugWorld.userCodeMap[currentThangID][currentSpellID].flow.states;
                     //we have to go to the second last flowState as we run the world for one additional frame
                     //to collect the flow
-                    value = _.last(flowStates[flowStates.length - 2].statements).variables[prop];
+                    value = _.last(flowStates[flowStates.length - 1].statements).variables[prop];
                 }
                 catch (e)
                 {
@@ -260,11 +260,12 @@ self.retrieveValueFromFrame = function retrieveValueFromFrame(args) {
     };
     self.enableFlowOnThangSpell(args.currentThangID, args.currentSpellID, args.userCodeMap);
     self.setupDebugWorldToRunUntilFrame(args);
-    self.debugWorld.loadFramesUntilFrame(
-        args.frame,
+    self.debugWorld.loadFrames(
         retrieveProperty.bind({},args.currentThangID, args.currentSpellID, args.variableChain),
         self.onDebugWorldError,
-        self.onDebugWorldProgress
+        self.onDebugWorldProgress,
+        false,
+        args.frame
     );
 };
 
@@ -297,8 +298,8 @@ self.setupDebugWorldToRunUntilFrame = function (args) {
     var stringifiedUserCodeMap = JSON.stringify(args.userCodeMap);
     var userCodeMapHasChanged = ! _.isEqual(self.currentUserCodeMapCopy, stringifiedUserCodeMap);
     self.currentUserCodeMapCopy = stringifiedUserCodeMap;
-    if (!self.debugWorld || userCodeMapHasChanged || args.frame != self.currentDebugWorldFrame) {
-        self.invalidateCache();
+    if (args.frame != self.currentDebugWorldFrame) self.invalidateCache();
+    if (!self.debugWorld || userCodeMapHasChanged || args.frame < self.currentDebugWorldFrame) {
         try {
             self.debugWorld = new World(args.worldName, args.userCodeMap);
             if (args.level)
@@ -314,23 +315,18 @@ self.setupDebugWorldToRunUntilFrame = function (args) {
             return;
         }
         Math.random = self.debugWorld.rand.randf;  // so user code is predictable
-
-        self.debugWorld.totalFrames = args.frame; //hack to work around error checking
-        self.currentDebugWorldFrame = args.frame;
     }
+    self.debugWorld.totalFrames = args.frame; //hack to work around error checking
+    self.currentDebugWorldFrame = args.frame;
 };
-self.runDebugWorldUntilFrame = function (args) {
-    self.setupDebugWorldToRunUntilFrame(args);
 
-    self.debugWorld.loadFramesUntilFrame(args.frame, self.onDebugWorldLoaded, self.onDebugWorldError, self.onDebugWorldProgress);
-
-};
 
 self.onDebugWorldLoaded = function onDebugWorldLoaded() {
     console.log("World loaded!");
 };
 
 self.onDebugWorldError = function onDebugWorldError(error) {
+
     if(!error.isUserCodeProblem) {
         console.log("Debug Non-UserCodeError:", error.toString() + "\n" + error.stack || error.stackTrace);
     }
@@ -357,7 +353,7 @@ self.runWorld = function runWorld(args) {
   self.firstWorld = args.firstWorld;
   self.postedErrors = false;
   self.logsLogged = 0;
-  
+
   try {
     self.world = new World(args.worldName, args.userCodeMap);
     if(args.level)
diff --git a/app/lib/surface/Surface.coffee b/app/lib/surface/Surface.coffee
index 3ead94dd8..04b54a7e4 100644
--- a/app/lib/surface/Surface.coffee
+++ b/app/lib/surface/Surface.coffee
@@ -593,8 +593,6 @@ module.exports = Surface = class Surface extends CocoClass
     @paths.parent.removeChild @paths
     @paths = null
 
-  # Screenshot
-
   screenshot: (scale=0.25, format='image/jpeg', quality=0.8, zoom=2) ->
     # Quality doesn't work with image/png, just image/jpeg and image/webp
     [w, h] = [@camera.canvasWidth, @camera.canvasHeight]
@@ -604,6 +602,5 @@ module.exports = Surface = class Surface extends CocoClass
     #console.log "Screenshot with scale", scale, "format", format, "quality", quality, "was", Math.floor(imageData.length / 1024), "kB"
     screenshot = document.createElement("img")
     screenshot.src = imageData
-    #$('body').append(screenshot)
     @stage.uncache()
     imageData
diff --git a/app/lib/world/world.coffee b/app/lib/world/world.coffee
index 76bacd6bf..3da7ae6df 100644
--- a/app/lib/world/world.coffee
+++ b/app/lib/world/world.coffee
@@ -71,14 +71,18 @@ module.exports = class World
     (@runtimeErrors ?= []).push error
     (@unhandledRuntimeErrors ?= []).push error
 
-  loadFrames: (loadedCallback, errorCallback, loadProgressCallback, skipDeferredLoading) ->
+  loadFrames: (loadedCallback, errorCallback, loadProgressCallback, skipDeferredLoading, loadUntilFrame) ->
     return if @aborted
     unless @thangs.length
       console.log "Warning: loadFrames called on empty World (no thangs)."
     t1 = now()
     @t0 ?= t1
+    if loadUntilFrame
+      frameToLoadUntil = loadUntilFrame + 1
+    else
+      frameToLoadUntil = @totalFrames
     i = @frames.length
-    while i < @totalFrames
+    while i < frameToLoadUntil
       try
         @getFrame(i)
         ++i  # increment this after we have succeeded in getting the frame, otherwise we'll have to do that frame again
@@ -95,43 +99,19 @@ module.exports = class World
         if t2 - @t0 > 1000
           console.log('  Loaded', i, 'of', @totalFrames, "(+" + (t2 - @t0).toFixed(0) + "ms)")
           @t0 = t2
-        continueFn = => @loadFrames(loadedCallback, errorCallback, loadProgressCallback, skipDeferredLoading)
+        continueFn = => 
+          if loadUntilFrame
+            @loadFrames(loadedCallback,errorCallback,loadProgressCallback, skipDeferredLoading, loadUntilFrame)
+          else
+            @loadFrames(loadedCallback, errorCallback, loadProgressCallback, skipDeferredLoading)
         if skipDeferredLoading
           continueFn()
         else
           setTimeout(continueFn, 0)
         return
-    @ended = true
-    system.finish @thangs for system in @systems
-    loadProgressCallback? 1
-    loadedCallback()
-
-  loadFramesUntilFrame: (frameToLoadUntil, loadedCallback, errorCallback, loadProgressCallback) ->
-    return if @aborted
-    unless @thangs.length
-      console.log "Warning: loadFrames called on empty World"
-    t1 = now()
-    @t0 ?= t1
-    i = @frames.length
-    while i <= frameToLoadUntil #state is gathered at next frame 
-      try
-        @getFrame(i)
-        ++i  # increment this after we have succeeded in getting the frame, otherwise we'll have to do that frame again
-      catch error
-      # Not an Aether.errors.UserCodeError; maybe we can't recover
-        @addError error
-      for error in (@unhandledRuntimeErrors ? [])
-        return unless errorCallback error  # errorCallback tells us whether the error is recoverable
-      @unhandledRuntimeErrors = []
-      t2 = now()
-      if t2 - t1 > PROGRESS_UPDATE_INTERVAL
-        loadProgressCallback? i / @totalFrames
-        t1 = t2
-        if t2 - @t0 > 1000
-          console.log('  Loaded', i, 'of', frameToLoadUntil, "(+" + (t2 - @t0).toFixed(0) + "ms)")
-          @t0 = t2
-        setTimeout((=> @loadFrames(loadedCallback, errorCallback, loadProgressCallback)), 0)
-        return
+    unless loadUntilFrame
+      @ended = true
+      system.finish @thangs for system in @systems
     loadProgressCallback? 1
     loadedCallback()
 
diff --git a/app/views/play/level/tome/spell_debug_view.coffee b/app/views/play/level/tome/spell_debug_view.coffee
index 0767b9e88..43e6db210 100644
--- a/app/views/play/level/tome/spell_debug_view.coffee
+++ b/app/views/play/level/tome/spell_debug_view.coffee
@@ -15,6 +15,7 @@ module.exports = class DebugView extends View
     'god:new-world-created': 'onNewWorld'
     'god:debug-value-return': 'handleDebugValue'
     'tome:spell-shown': 'changeCurrentThangAndSpell'
+    'surface:frame-changed': 'onFrameChanged'
 
   events: {}
 
@@ -24,7 +25,6 @@ module.exports = class DebugView extends View
     @thang = options.thang
     @spell = options.spell
     @variableStates = {}
-
     @globals = {Math: Math, _: _, String: String, Number: Number, Array: Array, Object: Object}  # ... add more as documented
     for className, serializedClass of serializedClasses
       @globals[className] = serializedClass
@@ -93,13 +93,17 @@ module.exports = class DebugView extends View
 
   onNewWorld: (e) ->
     @thang = @options.thang = e.world.thangMap[@thang.id] if @thang
-
+    
+  onFrameChanged: (data) ->
+    @currentFrame = data.frame
+    
   update: ->
     if @variableChain
       Backbone.Mediator.publish 'tome:spell-debug-value-request',
         thangID: @thang.id
         spellID: @spell.name
         variableChain: @variableChain
+        frame: @currentFrame
       @$el.find("code").text "Finding value..."
       @$el.show().css(@pos)
     else