Fixed debugger errors in many files and optimized some scenes/code

Levels/Objects/Chest.gd

@@ -1,38 +1,33 @@
 extends AnimatedSprite
 
-export(PackedScene) var object_scene: PackedScene = null
+export var object_scene: PackedScene = null
 
-var is_player_inside: bool = false
-var is_opened: bool = false
 var has_key: bool = false
 
-onready var animation_player: AnimationPlayer = get_node("AnimationPlayer")
-onready var tween: Tween = get_node("Key/Tween")
 
 func _ready() -> void:
-    assert(object_scene!=null)
-    animation_player.play("closed")
+    assert(object_scene != null)
+    $AnimationPlayer.play('closed')
     $Key/KeySprite.visible = false
-    
-func _input(event: InputEvent) -> void:
-    if is_player_inside and not is_opened:
-      is_opened = true
-      animation_player.play("open")
-      _drop_object()
+    return
+
+
+func _on_area_body_entered(body: Node) -> void:
+    if body.is_in_group('player'):
+        $Area/CollisionShape2D.set_deferred('disabled', true)
+        $AnimationPlayer.play('open')
+        _drop_object()
+    return
+
 
 func _drop_object() -> void:
-    #print($Key.position)
     $Key/KeySprite.visible = true
-    tween.interpolate_property($Key, "position", Vector2(0,0), Vector2(0, -10), 1.0, Tween.TRANS_QUAD, 
-                              Tween.EASE_OUT)
-    tween.start()
-    yield(tween, "tween_completed")
-    $Key/KeySprite.visible = false
-    
-    
-func _on_Area2D_player_entered(_player: KinematicBody2D) -> void:
-    is_player_inside = true
-    
+    if not $Key/Tween.interpolate_property($Key, 'position', Vector2(0,0), Vector2(0, -10), 1.0,
+                                           Tween.TRANS_QUAD, Tween.EASE_OUT):
+        print('ERROR: Chest key animation has errors.')
+    if not $Key/Tween.start():
+        print('ERROR: Chest key animation failed to start.')
 
-func _on_Area2D_player_exited(_player: KinematicBody2D) -> void:
-    is_player_inside = false
+    yield($Key/Tween, 'tween_completed')
+    $Key/KeySprite.visible = false
+    return