Index: exec.c
==================================================================
--- exec.c
+++ exec.c
@@ -688,11 +688,11 @@
   restart:
   if(hit&0x100000) dir=o->dir;
   objF=obj_dir(obj,dir);
   if(objF==VOIDLINK) goto fail;
   oF=objects[objF];
-  hF=height_at(oF->x,oF->y);
+  hF=oF?height_at(oF->x,oF->y):0;
   if(dir&1) {
     // Diagonal movement
     objLF=obj_dir(obj,(dir+1)&7);
     objRF=obj_dir(obj,(dir-1)&7);
     vol=o->volume;
@@ -700,11 +700,11 @@
     if(objRF!=VOIDLINK) vol+=volume_at(objects[objRF]->x,objects[objRF]->y);
     if(vol<=max_volume) {
       objE=objF;
       while(objE!=VOIDLINK) {
         oE=objects[objE];
-        if(oE->height>0 && !(oE->oflags&(OF_VISUALONLY|OF_DESTROYED))) {
+        if(oE->height>0) {
           v=send_message(objE,obj,MSG_HIT,NVALUE(oE->x),NVALUE(oE->y),NVALUE(hit|0x80000));
           if(v.t) Throw("Type mismatch in HIT/HITBY");
           hit=v.u&(classes[o->class]->cflags&CF_COMPATIBLE?0xFC098F7F:-1);
           if(hit&8) goto fail;
           if(!(hit&0x11)) {
@@ -717,29 +717,30 @@
         objE=obj_below(objE);
       }
       if(!(hit&0x402008)) {
         if(hF<=o->climb || (hit&0x200000)) {
           if(hit&0x20000) goto success;
+          if(!oF) goto fail;
           if(move_to(from,obj,oF->x,oF->y)) goto success; else goto fail;
         }
       }
     } else {
       // Volume is too much; hit the objects it won't go between
       objE=objLF;
       while(objE!=VOIDLINK) {
         oE=objects[objE];
-        if(oE->height>0 && !(oE->oflags&(OF_VISUALONLY|OF_DESTROYED))) {
+        if(oE->height>0) {
           v=send_message(objE,obj,MSG_HIT,NVALUE(oE->x),NVALUE(oE->y),NVALUE(0x80008));
           if(v.t) Throw("Type mismatch in HIT/HITBY");
           if(!(v.u&1)) v=send_message(obj,objE,MSG_HITBY,NVALUE(o->x),NVALUE(o->y),NVALUE(v.u|0x80008));
         }
         objE=obj_below(objE);
       }
       objE=objRF;
       while(objE!=VOIDLINK) {
         oE=objects[objE];
-        if(oE->height>0 && !(oE->oflags&(OF_VISUALONLY|OF_DESTROYED))) {
+        if(oE->height>0) {
           v=send_message(objE,obj,MSG_HIT,NVALUE(oE->x),NVALUE(oE->y),NVALUE(0x80008));
           if(v.t) Throw("Type mismatch in HIT/HITBY");
           if(!(v.u&1)) v=send_message(obj,objE,MSG_HITBY,NVALUE(o->x),NVALUE(o->y),NVALUE(v.u|0x80008));
         }
         objE=obj_below(objE);
@@ -749,11 +750,11 @@
     // Orthogonal movement
     if(hit) hit=(hit&0x0C000000)|0x800;
     objE=objF;
     while(objE!=VOIDLINK) {
       oE=objects[objE];
-      if(oE->height>0 && !(oE->oflags&(OF_VISUALONLY|OF_DESTROYED))) {
+      if(oE->height>0) {
         hit&=~7;
         // HIT/HITBY messages
         v=send_message(objE,obj,MSG_HIT,NVALUE(oE->x),NVALUE(oE->y),NVALUE(hit));
         if(v.t) Throw("Type mismatch in HIT/HITBY");
         hit|=v.u&(classes[o->class]->cflags&CF_COMPATIBLE?0xFC098F7F:-1);
@@ -785,10 +786,11 @@
     if(hit&0x2008) goto fail;
     if((hit&0x48000)==0x8000) goto restart;
     if(!(hit&0x400000)) {
       if(hF<=o->climb || (hit&0x200000)) {
         if(hit&0x20000) goto success;
+        if(!oF) goto fail;
         if(move_to(from,obj,oF->x,oF->y)) goto success; else goto fail;
       }
     }
     // Sliding
     if(hit&0x80) goto fail;
@@ -1492,14 +1494,14 @@
   free(objects);
   objects=0;
   gameover=0;
 }
 
-static Uint8 execute_animation(Uint8 clock,Uint32 obj) {
+static void execute_animation(Uint32 obj) {
   Object*o=objects[obj];
   Animation*a=o->anim;
-  if(!(a->step[a->lstep].flag&ANI_ONCE)) return clock;
+  if(!(a->step[a->lstep].flag&ANI_ONCE)) return;
   if(a->ltime>=a->step[a->lstep].speed) {
     a->ltime=0;
     if(o->image==a->step[a->lstep].end) {
       a->status&=~ANISTAT_LOGICAL;
       if(classes[o->class]->cflags&CF_COMPATIBLE) lastimage_processing=1;
@@ -1507,22 +1509,23 @@
       lastimage_processing=0;
     } else {
       if(a->step[a->lstep].start>a->step[a->lstep].end) --o->image; else ++o->image;
     }
   }
-  if(!(a->status&ANISTAT_LOGICAL) || !(a->step[a->lstep].flag&ANI_ONCE)) return clock;
-  if(clock>a->step[a->lstep].speed-a->ltime) return a->step[a->lstep].speed-a->ltime;
-  return clock;
 }
 
 const char*execute_turn(int key) {
   Uint8 busy,clock;
   Uint32 m,n,turn;
   Object*o;
   Value v;
   int i;
-  if(!key) return 0;
+  if(!key) {
+    // This is part of initialization; if anything triggered, it must be executed now
+    all_flushed=1;
+    goto trig;
+  }
   if(setjmp(my_env)) return my_error;
   if(quiz_text) {
     sqlite3_free(quiz_text);
     quiz_text=0;
     if(key_ignored) {
@@ -1595,11 +1598,11 @@
         if(o->arrived) {
           send_message(VOIDLINK,n,MSG_ARRIVED,NVALUE(0),NVALUE(0),NVALUE(turn));
           o->arrived=0;
           busy=1;
         }
-        if(o->anim && (o->anim->status&ANISTAT_LOGICAL)) clock=execute_animation(clock,n);
+        if(o->anim && (o->anim->status&ANISTAT_LOGICAL)) execute_animation(n);
         if(o->oflags&(OF_BUSY|OF_USERSIGNAL)) busy=1;
       } else {
         o->departed2=o->departed;
         o->departed=0;
         o->arrived2=o->arrived;
@@ -1616,11 +1619,11 @@
       if(o->oflags&OF_MOVED2) send_message(VOIDLINK,n,MSG_MOVED,NVALUE(0),NVALUE(0),NVALUE(turn)),busy=1;
       if(o->departed2) send_message(VOIDLINK,n,MSG_DEPARTED,NVALUE(o->departed2),NVALUE(0),NVALUE(turn)),busy=1;
       if(o->arrived2) send_message(VOIDLINK,n,MSG_ARRIVED,NVALUE(o->arrived2),NVALUE(0),NVALUE(turn)),busy=1;
       o->oflags&=~OF_MOVED2;
       o->arrived2=o->departed2=0;
-      if(o->anim && (o->anim->status&ANISTAT_LOGICAL)) clock=execute_animation(clock,n);
+      if(o->anim && (o->anim->status&ANISTAT_LOGICAL)) execute_animation(n);
       if(o->oflags&(OF_BUSY|OF_USERSIGNAL)) busy=1;
     }
     n=o->prev;
   }
   // Ending phase
@@ -1634,22 +1637,30 @@
     }
     turn++;
     if(!busy) all_flushed=1;
   }
   // Clock phase
-  if(!clock) clock=1;
+  n=lastobj;
+  while(n!=VOIDLINK) {
+    o=objects[n];
+    if(o->arrived || o->departed) goto trig;
+    if(o->oflags&OF_MOVED) goto trig;
+    if(o->anim && (o->anim->status&ANISTAT_LOGICAL) && (o->anim->step[o->anim->lstep].flag&ANI_ONCE)) {
+      if(o->anim->ltime>=o->anim->step[o->anim->lstep].speed) goto trig;
+      if(clock>o->anim->step[o->anim->lstep].speed-o->anim->ltime) clock=o->anim->step[o->anim->lstep].speed-o->anim->ltime;
+    }
+    n=o->prev;
+  }
   n=lastobj;
   while(n!=VOIDLINK) {
     o=objects[n];
     if(o->oflags&(OF_BUSY|OF_USERSIGNAL|OF_MOVED)) busy=1;
     if(o->arrived || o->departed) busy=1;
-    if(o->anim && (o->anim->status&ANISTAT_LOGICAL)) {
-      if(o->anim->step[o->anim->lstep].flag&ANI_ONCE) {
-        i=o->anim->ltime+clock;
-        o->anim->ltime=i>255?255:i;
-        busy=1;
-      }
+    if(o->anim && (o->anim->status&ANISTAT_LOGICAL) && (o->anim->step[o->anim->lstep].flag&ANI_ONCE)) {
+      i=o->anim->ltime+clock;
+      o->anim->ltime=i>255?255:i;
+      busy=1;
     }
     n=o->prev;
   }
   if(busy) goto trig;
   // Cleanup phase
@@ -1672,8 +1683,8 @@
   vstackptr=0;
   move_number=0;
   current_key=0;
   broadcast(VOIDLINK,0,MSG_INIT,NVALUE(0),NVALUE(0),NVALUE(0),0);
   broadcast(VOIDLINK,0,MSG_POSTINIT,NVALUE(0),NVALUE(0),NVALUE(0),0);
-  if(generation_number<=TY_MAXTYPE) return "Too many generations of objects";
-  return 0;
+  if(gameover) return 0;
+  return execute_turn(0);
 }

Index: game.c
==================================================================
--- game.c
+++ game.c
@@ -491,11 +491,11 @@
           SDL_SetTimer(0,0);
           return;
         }
         if(inputs_count) {
           //TODO: Check for solution replay
-          for(i=0;i<inputs_count && !gameover;i++) input_move(inputs[i]);
+          for(i=0;i<inputs_count && !gameover;i++) if(inputs[i]) input_move(inputs[i]);
           inputs_count=0;
         }
         redraw_game();
         timerflag=0; // ensure we have not missed a timer event
         break;