diff --git a/CHANGELOG.md b/CHANGELOG.md
index face2156..9bdf94d3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## [4.0.0-alpha.3](https://github.com/godot-escoria/escoria-demo-game/compare/v0.0.0...v4.0.0-alpha.3) (2021-10-19)
+
+
+
 ## [4.0.0-alpha.2](https://github.com/godot-escoria/escoria-demo-game/compare/v0.0.0...v4.0.0-alpha.2) (2021-10-17)
 
 
diff --git a/addons/escoria-core/game/core-scripts/esc/commands/change_scene.gd b/addons/escoria-core/game/core-scripts/esc/commands/change_scene.gd
index a825b1cf..e0b51503 100644
--- a/addons/escoria-core/game/core-scripts/esc/commands/change_scene.gd
+++ b/addons/escoria-core/game/core-scripts/esc/commands/change_scene.gd
@@ -83,6 +83,10 @@ func run(command_params: Array) -> int:
 			]
 		)
 	
+	if escoria.main.current_scene \
+		and escoria.game_scene.get_parent() == escoria.main.current_scene:
+		escoria.main.current_scene.remove_child(escoria.game_scene)
+	
 	# Load room scene
 	var room_scene = res_room.instance()
 	if room_scene:
diff --git a/addons/escoria-core/game/core-scripts/esc/commands/inc_global.gd b/addons/escoria-core/game/core-scripts/esc/commands/inc_global.gd
index 41697618..d409dfa8 100644
--- a/addons/escoria-core/game/core-scripts/esc/commands/inc_global.gd
+++ b/addons/escoria-core/game/core-scripts/esc/commands/inc_global.gd
@@ -27,7 +27,7 @@ func validate(arguments: Array):
 			]
 		)
 		return false
-	if not escoria.globals_manager.get(arguments[0]) is int:
+	if not escoria.globals_manager.get_global(arguments[0]) is int:
 		escoria.logger.report_errors(
 			"inc_global: invalid global",
 			[
diff --git a/addons/escoria-core/game/main.gd b/addons/escoria-core/game/main.gd
index 26138bf6..9f1c6648 100644
--- a/addons/escoria-core/game/main.gd
+++ b/addons/escoria-core/game/main.gd
@@ -40,9 +40,9 @@ func set_scene(p_scene: Node) -> void:
 	if current_scene != null:
 		clear_scene()
 
-	add_child(p_scene) 
+	if not p_scene in get_children():
+		add_child(p_scene) 
 	move_child(p_scene, 0)
-
 	current_scene = p_scene
 	check_game_scene_methods()
 
@@ -59,7 +59,8 @@ func clear_scene() -> void:
 	escoria.action_manager.clear_current_action()
 	escoria.action_manager.clear_current_tool()
 	
-	current_scene.remove_child(escoria.game_scene)
+	if escoria.game_scene.get_parent() == current_scene:
+		current_scene.remove_child(escoria.game_scene)
 
 	remove_child(current_scene)
 	current_scene.free()
diff --git a/addons/escoria-core/game/scenes/camera_player/esc_camera.gd b/addons/escoria-core/game/scenes/camera_player/esc_camera.gd
index a7e2914f..15d356e9 100644
--- a/addons/escoria-core/game/scenes/camera_player/esc_camera.gd
+++ b/addons/escoria-core/game/scenes/camera_player/esc_camera.gd
@@ -195,7 +195,7 @@ func target_reached():
 func _process(_delta):
 	zoom_transform = self.get_canvas_transform()
 
-	if follow_target and not tween.is_active() and follow_target.has_moved():
+	if is_instance_valid(follow_target) and not tween.is_active() and follow_target.has_moved():
 		self.global_position = follow_target.global_position
 
 func _ready():
diff --git a/addons/escoria-ui-9verbs/game.gd b/addons/escoria-ui-9verbs/game.gd
index 05cd7a3c..260c68ff 100644
--- a/addons/escoria-ui-9verbs/game.gd
+++ b/addons/escoria-ui-9verbs/game.gd
@@ -39,7 +39,7 @@ onready var pause_menu = $ui/pause_menu
 onready var inventory_ui = $ui/Control/panel_down/VBoxContainer/HBoxContainer\
 		/InventoryMargin/inventory_ui
 
-func _ready():
+func _enter_tree():
 	ProjectSettings.set_setting("escoria/ui/tooltip_follows_mouse", false)
 	escoria.action_manager.connect(
 		"action_finished", 
@@ -47,6 +47,13 @@ func _ready():
 		"_on_action_finished"
 	)
 
+func _exit_tree():
+	escoria.action_manager.disconnect(
+		"action_finished", 
+		self, 
+		"_on_action_finished"
+	)
+
 
 ## BACKGROUND ## 
 
diff --git a/addons/escoria-ui-simplemouse/game.gd b/addons/escoria-ui-simplemouse/game.gd
index 3c10d6f5..ba402f22 100644
--- a/addons/escoria-ui-simplemouse/game.gd
+++ b/addons/escoria-ui-simplemouse/game.gd
@@ -38,17 +38,24 @@ func _enter_tree():
 		"_on_action_finished"
 	)
 
+func _exit_tree():
+	escoria.action_manager.disconnect(
+		"action_finished", 
+		self, 
+		"_on_action_finished"
+	)
 
 ## BACKGROUND ## 
 
 func left_click_on_bg(position: Vector2) -> void:
-	escoria.do(
-		"walk", 
-		[escoria.main.current_scene.player.global_id, position],
-		true
-	)
-	$CanvasLayer/ui/HBoxContainer/verbs_menu.set_by_name("walk")
-	$CanvasLayer/ui/HBoxContainer/verbs_menu.clear_tool_texture()
+	if escoria.main.current_scene.player:
+		escoria.do(
+			"walk", 
+			[escoria.main.current_scene.player.global_id, position],
+			true
+		)
+		$CanvasLayer/ui/HBoxContainer/verbs_menu.set_by_name("walk")
+		$CanvasLayer/ui/HBoxContainer/verbs_menu.clear_tool_texture()
 	
 func right_click_on_bg(position: Vector2) -> void:
 	mousewheel_action(1)
diff --git a/project.godot b/project.godot
index 1cdaa405..30a33ed0 100644
--- a/project.godot
+++ b/project.godot
@@ -672,7 +672,6 @@ ui/default_transition="curtain"
 ui/transition_paths=[ "res://addons/escoria-core/game/scenes/transitions/shaders/" ]
 ui/main_menu_scene="res://game/ui/commons/main_menu/main_menu.tscn"
 ui/pause_menu_scene="res://game/ui/commons/pause_menu/pause_menu.tscn"
-internals/save_data=""
 
 [input]