Your current LSS Browsing data will be saved upon playing a custom level, and will return you to where you originally were, before play

Scripts/Classes/Editor/LevelEditor.gd

@@ -240,7 +240,6 @@ func cleanup() -> void:
 	playing_level = !playing_level
 	play_pipe_transition = false
 	play_door_transition = false
-	Door.unlocked_doors = []
 	LevelPersistance.reset_states()
 	KeyItem.total_collected = 0
 	Global.get_node("GameHUD").visible = playing_level
@@ -656,8 +655,9 @@ func transition_to_sublevel(sub_lvl_idx := 0) -> void:
 		level_file = $LevelSaver.save_level(level_name, level_author, level_desc, difficulty)
 		LevelPersistance.reset_states()
 	sub_level_id = sub_lvl_idx
-	$LevelLoader.load_level(sub_lvl_idx)
-	Global.do_fake_transition(0.1)
+	await $LevelLoader.load_level(sub_lvl_idx)
+	if Settings.file.visuals.transition_animation == 0:
+		Global.do_fake_transition(0.1)
 	await get_tree().physics_frame
 	if (play_pipe_transition or play_door_transition) and play_transition:
 		parse_tiles()

Scripts/Classes/Entities/Objects/Door.gd

@@ -5,7 +5,10 @@ extends Node2D
 
 @export_enum("0", "1", "2", "3", "4") var sublevel_id := 0
 
-@export var locked := false
+@export var locked := false:
+	set(value):
+		locked = value
+		pass
 @export var start_locked := false
 
 signal updated
@@ -23,6 +26,7 @@ static var same_scene_exiting_door: Door = null
 func _ready() -> void:
 	if start_locked:
 		locked = true
+	await get_tree().physics_frame
 	if locked:
 		check_if_unlocked(false)
 
@@ -42,6 +46,7 @@ func _physics_process(_delta: float) -> void:
 
 func check_if_unlocked(do_animation := true) -> void:
 	if locked:
+		print(unlocked_doors)
 		if unlocked_doors.has(door_id):
 			locked = false
 			$Sprite.play("Idle")
@@ -113,7 +118,6 @@ func player_enter(player: Player) -> void:
 	else:
 		same_scene_exiting_door = null
 		Global.level_editor.transition_to_sublevel(sublevel_id)
-	$Sprite.play("Idle")
 	can_enter = true
 
 func freeze_player(player: Player) -> void:

Scripts/Classes/Singletons/Global.gd

@@ -265,6 +265,7 @@ func reset_values() -> void:
 	PlayerGhost.idx = 0
 	Checkpoint.passed = false
 	Checkpoint.sublevel_id = 0
+	Door.unlocked_doors = []
 	Level.start_level_path = Level.get_scene_string(Global.world_num, Global.level_num)
 	LevelPersistance.reset_states()
 	Level.first_load = true