diff --git a/client/scripts/rendering/world_renderer.gd b/client/scripts/rendering/world_renderer.gd
index 7e2d9421a..ad0c140d6 100644
--- a/client/scripts/rendering/world_renderer.gd
+++ b/client/scripts/rendering/world_renderer.gd
@@ -8,30 +8,29 @@ extends Node2D
 @onready var fog_renderer = $FogOverlay
 @onready var entity_renderer = $Entities
 
-var _last_tile_count: int = 0
-var _last_visible_count: int = 0
+var _last_tick: int = -1
 
 func _ready() -> void:
 	print("WorldRenderer: Initialized")
 
-# Called each frame to update visuals from game state
+# Called each frame to update visuals from game state.
+# Uses tick-based invalidation — re-renders all layers when a new snapshot arrives.
 func update_from_state() -> void:
-	var tile_count := GameState.visible_tiles.size()
-	var visible_count := GameState.visible_positions.size()
+	var tick := GameState.current_tick
+	if tick == _last_tick:
+		return
+	_last_tick = tick
 
-	# Update tiles when tile data changes (new chunks loaded, D-012)
+	# Update tiles (may include new chunks or modified tiles)
 	if tile_renderer and tile_renderer.has_method("update_tiles"):
-		if tile_count > 0 and tile_count != _last_tile_count:
+		if GameState.visible_tiles.size() > 0:
 			tile_renderer.update_tiles(GameState.visible_tiles)
 			if fog_renderer and fog_renderer.has_method("register_tile_positions"):
 				fog_renderer.register_tile_positions(GameState.visible_tiles)
-			_last_tile_count = tile_count
 
-	# Update fog overlay when visibility changes
+	# Update fog overlay from visibility data
 	if fog_renderer and fog_renderer.has_method("update_fog"):
-		if visible_count != _last_visible_count:
-			fog_renderer.update_fog(GameState.visible_positions, GameState.player_position)
-			_last_visible_count = visible_count
+		fog_renderer.update_fog(GameState.visible_positions, GameState.player_position)
 
 	# Update entity sprites
 	if entity_renderer and entity_renderer.has_method("update_entities"):
diff --git a/client/tests/test_rendering.gd b/client/tests/test_rendering.gd
index ad28cbb82..c51fa31d8 100644
--- a/client/tests/test_rendering.gd
+++ b/client/tests/test_rendering.gd
@@ -31,6 +31,12 @@ func test_tile_size_constant() -> void:
 
 # -- GameState: tile and visibility data --
 
+func test_game_state_tick_advances() -> void:
+	GameState.apply_snapshot({"tick": 1, "tiles": _test_tiles})
+	assert_that(GameState.current_tick).is_equal(1)
+	GameState.apply_snapshot({"tick": 2, "tiles": _test_tiles})
+	assert_that(GameState.current_tick).is_equal(2)
+
 func test_game_state_stores_tiles() -> void:
 	GameState.apply_snapshot({"tick": 1, "tiles": _test_tiles})
 	assert_that(GameState.visible_tiles.size()).is_equal(5)
@@ -49,6 +55,23 @@ func test_game_state_clears_old_visible_positions() -> void:
 	assert_that(GameState.visible_positions.size()).is_equal(2)
 	assert_that(GameState.visible_positions.has(Vector2i(1, 1))).is_false()
 
+func test_game_state_same_count_different_tiles_new_tick() -> void:
+	var tiles_a := [{"x": 0, "y": 0, "z": 0, "type": "floor"}]
+	var tiles_b := [{"x": 0, "y": 0, "z": 0, "type": "door"}]
+	GameState.apply_snapshot({"tick": 1, "tiles": tiles_a})
+	assert_that(GameState.visible_tiles[0].type).is_equal("floor")
+	GameState.apply_snapshot({"tick": 2, "tiles": tiles_b})
+	assert_that(GameState.current_tick).is_equal(2)
+	assert_that(GameState.visible_tiles[0].type).is_equal("door")
+
+func test_game_state_same_count_different_visibility_new_tick() -> void:
+	GameState.apply_snapshot({"tick": 1, "visible_positions": [{"x": 1, "y": 1}]})
+	assert_that(GameState.visible_positions.has(Vector2i(1, 1))).is_true()
+	GameState.apply_snapshot({"tick": 2, "visible_positions": [{"x": 2, "y": 2}]})
+	assert_that(GameState.current_tick).is_equal(2)
+	assert_that(GameState.visible_positions.has(Vector2i(1, 1))).is_false()
+	assert_that(GameState.visible_positions.has(Vector2i(2, 2))).is_true()
+
 func test_game_state_warns_on_missing_player() -> void:
 	GameState.player_entity_id = 999
 	GameState.player_position = Vector2(5, 5)