diff --git a/scripts/editor.js b/scripts/editor.js
index 20ce506..534dc2a 100644
--- a/scripts/editor.js
+++ b/scripts/editor.js
@@ -629,7 +629,7 @@ var editor = {
   },
 
   /* Checking to save an entity as a subtype. */
-  /* sub is the name of the type; obj is the object to save it as */
+  /* sub is the name of the (sub)type; obj is the object to save it as */
   saveas_check(sub, obj) {
     if (!sub) return;
     obj ??= editor.selectlist[0];
@@ -644,18 +644,20 @@ var editor = {
       var saveobj = obj.json_obj();
       IO.slurpwrite(JSON.stringify(saveobj,null,1), path);
 
-
       if (obj === editor.edit_level) {
-        obj.clear();
-	var nobj = editor.edit_level.spawn(sub);
-	editor.selectlist = [nobj];
-	return;
+        if (obj === editor.desktop) {
+	  obj.clear();
+    	  var nobj = editor.edit_level.spawn(sub);
+	  editor.selectlist = [nobj];
+	  return;
+	}
+	editor.edit_level = editor.edit_level.level;
       }
-      
-      var t = obj.transform();      
-      obj.kill();
+
+      var t = obj.transform();
       editor.unselect();
-      obj = editor.load(sub);
+      obj.kill();
+      obj = editor.edit_level.spawn(sub);
       obj.pos = t.pos;
       obj.angle = t.angle;
     }
@@ -874,12 +876,18 @@ editor.inputs['C-s'] = function() {
   Log.warn(`Wrote to file ${path}`);
 
   Object.values(saveobj.objects).forEach(function(x) { x._ed.check_dirty(); });
+
+  Game.objects.forEach(function(x) {
+    if (x._ed.dirty) return;
+    x.revert();
+    x._ed.check_dirty();
+  });
 };
 editor.inputs['C-s'].doc = "Save selected.";
 
 editor.inputs['C-S'] = function() {
   if (editor.selectlist.length !== 1) return;
-  saveaspanel.stem = this.selectlist[0].toString();
+  saveaspanel.stem = this.selectlist[0].ur;
   editor.openpanel(saveaspanel);
 };
 editor.inputs['C-S'].doc = "Save selected as.";
@@ -1077,7 +1085,7 @@ editor.inputs.mm = function() {
 
   var o = editor.try_pick();
   if (!o) return;
-  editor.selectlist = [o];
+//  editor.selectlist = [o];
   editor.grabselect = [o];
 };
 editor.inputs['C-mm'] = editor.inputs.mm;
diff --git a/scripts/engine.js b/scripts/engine.js
index 1500995..8cf1bf1 100644
--- a/scripts/engine.js
+++ b/scripts/engine.js
@@ -790,7 +790,6 @@ preprimum.gscale = function() { return 1; };
 preprimum.pos = [0,0];
 preprimum.angle = 0;
 preprimum.remove_obj = function() {};
-preprimum.instances = [];
 preprimum.toString = function() { return "preprimum"; };
 globalThis.World = preprimum.make(preprimum);
 globalThis.Primum = World;
@@ -800,6 +799,8 @@ Primum.toString = function() { return "Primum"; };
 Primum._ed.selectable = false;
 Primum._ed.check_dirty = function() { };
 Primum._ed.dirty = false;
+Primum.revert = function(){};
+Primum.ur = undefined;
 globalThis.World.reparent = function(parent) { Log.warn("Cannot reparent the Primum."); }
 Game.view_camera(Primum.spawn(ur.camera2d));
 }
diff --git a/scripts/entity.js b/scripts/entity.js
index 3e1651b..4644e25 100644
--- a/scripts/entity.js
+++ b/scripts/entity.js
@@ -238,7 +238,11 @@ var gameobject = {
 
   /* Make a unique object the same as its prototype */
   revert() {
-    Object.merge(this,this.__proto__);
+    var jobj = this.json_obj();
+    delete jobj.objects;
+    Object.keys(jobj).forEach(function(x) {
+      this[x] = this.__proto__[x];
+    }, this);
     this.sync();
   },
 
@@ -416,7 +420,10 @@ var gameobject = {
 
 	  Player.do_uncontrol(this);
 	  Register.unregister_obj(this);
-//	  ur[this.ur].instances.remove(this);
+
+	  if (this.__proto__.instances)
+	    this.__proto__.instances.remove(this);
+	    
 	  this.body = -1;
 
 	  for (var key in this.components) {
@@ -446,7 +453,8 @@ var gameobject = {
     obj.make = undefined;
     obj.level = level;
 //    obj.toJSON = obj.transform_obj;
-//    this.instances.push(obj);
+    if (this.instances)
+      this.instances.push(obj);
 //    Log.warn(`Made an object from ${this.toString()}`);
 //    Log.warn(this.instances.length);
     obj.body = make_gameobject();
@@ -509,12 +517,10 @@ var gameobject = {
     obj.sync();
     gameobject.check_registers(obj);
 
+    if (data)
+      Object.dainty_assign(obj,data);
+
     if (Game.playing() && typeof obj.start === 'function') obj.start();
-/*      obj.objects.forEach(function(obj) {
-        if (Game.playing() && typeof obj.start === 'function') obj.start();            
-      });
-*/    
-    
     
     return obj;
   },
diff --git a/scripts/sound.js b/scripts/sound.js
index ee1d9ce..9464637 100644
--- a/scripts/sound.js
+++ b/scripts/sound.js
@@ -1,3 +1,7 @@
+var Audio = {
+    
+};
+
 var Music = {
   play(path) {
     Log.info("Playing " + path);
diff --git a/source/engine/debug/debugdraw.c b/source/engine/debug/debugdraw.c
index 5004253..9f94229 100644
--- a/source/engine/debug/debugdraw.c
+++ b/source/engine/debug/debugdraw.c
@@ -102,7 +102,7 @@ void debug_flush(HMM_Mat4 *view)
     sg_apply_bindings(&line_bind);
     sg_apply_uniforms(SG_SHADERSTAGE_VS,0,SG_RANGE_REF(*view));
     lfs_params_t lt;
-    lt.time = appTime;
+    lt.time = apptime();
     sg_apply_uniforms(SG_SHADERSTAGE_FS,0,SG_RANGE_REF(lt));
     sg_draw(line_sc,line_c,1);
    }
diff --git a/source/engine/debug/log.c b/source/engine/debug/log.c
index 9abd0b3..493881e 100644
--- a/source/engine/debug/log.c
+++ b/source/engine/debug/log.c
@@ -29,14 +29,12 @@ FILE *logfile = NULL;
 #define CONSOLE_BUF 1024*1024 /* 5MB */
 
 char *consolelog;
-FILE *consolefp;
 
 static FILE *sout;
 
 void log_init()
 {
   consolelog = malloc(CONSOLE_BUF+1);
-  consolefp = fmemopen(consolelog, CONSOLE_BUF+1,"w");
   sout = fdopen(dup(stdout),"w");
   sout = stdout;
 }
diff --git a/source/engine/ffi.c b/source/engine/ffi.c
index 68d3545..0e1da85 100644
--- a/source/engine/ffi.c
+++ b/source/engine/ffi.c
@@ -514,7 +514,7 @@ JSValue duk_cmd(JSContext *js, JSValueConst this, int argc, JSValueConst *argv)
     break;
 
   case 6:
-//    updateMS = js2number(argv[1]);
+    updateMS = js2number(argv[1]);
     break;
 
   case 7:
@@ -1047,7 +1047,7 @@ JSValue duk_cmd(JSContext *js, JSValueConst this, int argc, JSValueConst *argv)
       gif_rec_end(str);
       break;
     case 133:
-      ret = JS_NewFloat64(js, appTime);
+      ret = JS_NewFloat64(js, apptime());
       break;
 
     case 134:
diff --git a/source/engine/render.c b/source/engine/render.c
index deba60b..16235bc 100644
--- a/source/engine/render.c
+++ b/source/engine/render.c
@@ -56,7 +56,7 @@ void gif_rec_start(int w, int h, int cpf, int bitdepth)
   gif.cpf = cpf;
   gif.spf = cpf/100.0;
   gif.rec = 1;
-  gif.timer = appTime;
+  gif.timer = apptime();
   if (gif.buffer) free(gif.buffer);
   gif.buffer = malloc(gif.w*gif.h*4);
 
@@ -548,14 +548,14 @@ void openglRender(struct window *window) {
   full_2d_pass(window);
   sg_end_pass();
 
-  if (gif.rec && (appTime - gif.timer) > gif.spf) {
+  if (gif.rec && (apptime() - gif.timer) > gif.spf) {
     sg_begin_pass(sg_gif.pass, &pass_action);
     sg_apply_pipeline(sg_gif.pipe);
     sg_apply_bindings(&sg_gif.bind);
     sg_draw(0,6,1);
     sg_end_pass();
 
-    gif.timer = appTime;
+    gif.timer = apptime();
     sg_query_image_pixels(sg_gif.img, crt_post.bind.fs.samplers[0], gif.buffer, gif.w*gif.h*4);
     msf_gif_frame(&gif_state, gif.buffer, gif.cpf, gif.depth, gif.w * -4);
   }
diff --git a/source/engine/yugine.c b/source/engine/yugine.c
index 3452913..91ce461 100644
--- a/source/engine/yugine.c
+++ b/source/engine/yugine.c
@@ -54,12 +54,16 @@ static struct d_prof prof_input;
 static struct d_prof prof_physics;
 
 double physlag = 0;
-
 double physMS = 1 / 60.f;
+uint64_t physlast = 0;
+
+double updateMS = 1/60.f;
+uint64_t updatelast = 0;
 
 static int phys_step = 0;
 
-double appTime = 0;
+uint64_t start_t;
+uint64_t frame_t;
 
 static float timescale = 1.f;
 
@@ -139,6 +143,8 @@ void c_init() {
   window_set_icon("icons/moon.gif");  
   window_resize(sapp_width(), sapp_height());
   script_evalf("Game.init();");
+
+  
 }
 
 int frame_fps() {
@@ -147,34 +153,34 @@ int frame_fps() {
 
 static void process_frame()
 {
-    double elapsed = sapp_frame_duration();
-    appTime += elapsed;
+  double elapsed = stm_sec(stm_laptime(&frame_t));
+  physlag += elapsed;
 
     input_poll(0);
+    /* Timers all update every frame - once per monitor refresh */
     timer_update(elapsed, timescale);    
       
-    if (sim_play == SIM_PLAY || sim_play == SIM_STEP) {
+    if (sim_play == SIM_PLAY || sim_play == SIM_STEP && stm_sec(stm_diff(frame_t, updatelast)) > updateMS) {
+      double dt = stm_sec(stm_diff(frame_t, updatelast));
+      updatelast = frame_t;
       prof_start(&prof_update);
-
-      call_updates(elapsed * timescale);
+      call_updates(dt * timescale);
       prof(&prof_update);
 
-      physlag += elapsed;
-      while (physlag >= physMS) {
-        prof_start(&prof_physics);
-        phys_step = 1;
-        physlag -= physMS;
-        phys2d_update(physMS * timescale);
-	call_physics(physMS * timescale);
-        if (sim_play == SIM_STEP) sim_pause();
-        phys_step = 0;
-	prof(&prof_physics);
-      }
-
       if (sim_play == SIM_STEP)
         sim_pause();
     }
 
+    while ((sim_play == SIM_PLAY || sim_play == SIM_STEP) && physlag > physMS) {
+      physlag -= physMS;
+      prof_start(&prof_physics);
+      phys_step = 1;
+      phys2d_update(physMS * timescale);
+      call_physics(physMS * timescale);
+      phys_step = 0;
+      prof(&prof_physics);
+    }
+
     prof_start(&prof_draw);
     window_render(&mainwin);
     prof(&prof_draw);
@@ -338,6 +344,9 @@ int main(int argc, char **argv) {
   
 #endif
   stm_setup(); /* time */
+  start_t = frame_t = stm_now();
+  physlast = updatelast = start_t;
+  
   resources_init();
   phys2d_init();  
   script_startup();
@@ -366,3 +375,8 @@ int main(int argc, char **argv) {
 
   return 0;
 }
+
+double apptime()
+{
+  return stm_sec(stm_diff(start_t, stm_now()));
+}
diff --git a/source/engine/yugine.h b/source/engine/yugine.h
index 0d79e27..ba13a36 100644
--- a/source/engine/yugine.h
+++ b/source/engine/yugine.h
@@ -18,7 +18,7 @@ void app_name(char *name);
 int frame_fps();
 double get_timescale();
 
-extern double appTime;
+double apptime();
 extern double renderMS;
 extern double physMS;
 extern double updateMS;