diff --git a/js/game.js b/js/game.js
index f57a030..66d89b9 100644
--- a/js/game.js
+++ b/js/game.js
@@ -792,6 +792,7 @@ export class Level extends LevelInterface {
         }
 
         this._swap_players();
+        this._do_post_actor_phase();
 
         // Wire updates every frame, which means thrice per tic
         this._do_wire_phase();
@@ -805,6 +806,7 @@ export class Level extends LevelInterface {
     _advance_tic_lynx() {
         this._do_decision_phase();
         this._do_combined_action_phase(3);
+        this._do_post_actor_phase();
         this._do_wire_phase();
         this._do_wire_phase();
         this._do_wire_phase();
@@ -817,16 +819,19 @@ export class Level extends LevelInterface {
     _advance_tic_lynx60() {
         this._do_decision_phase(true);
         this._do_combined_action_phase(1, true);
+        this._do_post_actor_phase();
         this._do_wire_phase();
 
         this.frame_offset = 1;
         this._do_decision_phase(true);
         this._do_combined_action_phase(1, true);
+        this._do_post_actor_phase();
         this._do_wire_phase();
 
         this.frame_offset = 2;
         this._do_decision_phase();
         this._do_combined_action_phase(1);
+        this._do_post_actor_phase();
         this._do_wire_phase();
 
         this.frame_offset = 0;
@@ -846,6 +851,7 @@ export class Level extends LevelInterface {
 
             this._do_decision_phase(! is_decision_frame);
             this._do_combined_action_phase(1, ! is_decision_frame);
+            this._do_post_actor_phase();
             this._do_wire_phase();
 
             if (this.frame_offset === 2) {
@@ -903,6 +909,7 @@ export class Level extends LevelInterface {
         }
 
         this.sfx.set_player_position(this.player.cell);
+        this.pending_green_toggle = false;
     }
 
     // Decision phase: all actors decide on their movement "simultaneously"
@@ -1153,6 +1160,31 @@ export class Level extends LevelInterface {
         }
     }
 
+    _do_post_actor_phase() {
+        if (this.pending_green_toggle) {
+            // Swap green floors and walls
+            // TODO could probably make this more compact for undo purposes
+            for (let cell of this.linear_cells) {
+                let terrain = cell.get_terrain();
+                if (terrain.type.name === 'green_floor') {
+                    this.transmute_tile(terrain, 'green_wall');
+                }
+                else if (terrain.type.name === 'green_wall') {
+                    this.transmute_tile(terrain, 'green_floor');
+                }
+
+                let item = cell.get_item();
+                if (item && item.type.name === 'green_chip') {
+                    this.transmute_tile(item, 'green_bomb');
+                }
+                else if (item && item.type.name === 'green_bomb') {
+                    this.transmute_tile(item, 'green_chip');
+                }
+            }
+            this.pending_green_toggle = false;
+        }
+    }
+
     _do_cleanup_phase() {
         // Lynx compat: Any blue tank that still has the reversal flag set here, but is in motion,
         // should ignore it.  Unfortunately this has to be done as its own pass (as it is in Lynx!)
diff --git a/js/tiletypes.js b/js/tiletypes.js
index b551b73..04e4b21 100644
--- a/js/tiletypes.js
+++ b/js/tiletypes.js
@@ -1335,6 +1335,13 @@ const TILE_TYPES = {
     },
     green_floor: {
         layer: LAYERS.terrain,
+        blocks(me, level, other) {
+            // Toggle walls don't toggle until the end of the frame, but the collision takes into
+            // account whether a toggle is coming
+            return (
+                level.pending_green_toggle &&
+                (other.type.collision_mask & COLLISION.all_but_ghost));
+        },
         on_gray_button(me, level) {
             level.transmute_tile(me, 'green_wall');
         },
@@ -1344,7 +1351,12 @@ const TILE_TYPES = {
     },
     green_wall: {
         layer: LAYERS.terrain,
-        blocks_collision: COLLISION.all_but_ghost,
+        blocks(me, level, other) {
+            // Same as above
+            return (
+                ! level.pending_green_toggle &&
+                (other.type.collision_mask & COLLISION.all_but_ghost));
+        },
         on_gray_button(me, level) {
             level.transmute_tile(me, 'green_floor');
         },
@@ -2034,25 +2046,7 @@ const TILE_TYPES = {
     button_green: {
         layer: LAYERS.terrain,
         do_button(level) {
-            // Swap green floors and walls
-            // TODO could probably make this more compact for undo purposes
-            for (let cell of level.linear_cells) {
-                let terrain = cell.get_terrain();
-                if (terrain.type.name === 'green_floor') {
-                    level.transmute_tile(terrain, 'green_wall');
-                }
-                else if (terrain.type.name === 'green_wall') {
-                    level.transmute_tile(terrain, 'green_floor');
-                }
-
-                let item = cell.get_item();
-                if (item && item.type.name === 'green_chip') {
-                    level.transmute_tile(item, 'green_bomb');
-                }
-                else if (item && item.type.name === 'green_bomb') {
-                    level.transmute_tile(item, 'green_chip');
-                }
-            }
+            level.pending_green_toggle = ! level.pending_green_toggle;
         },
         on_arrive(me, level, other) {
             level.sfx.play_once('button-press', me.cell);