Initial scaffold: Godot 4.3 scenes, systems, and placeholders.

Wire all twelve levels with billboard prefabs, autoload systems (inventory, achievements, mock shop, DE/EN/BY), and satire audio locks so the Title→End flow is playable with placeholder assets.

scripts/player/player_controller.gd

@@ -0,0 +1,58 @@
+extends CharacterBody3D
+class_name PlayerController
+## Simple top-down-ish 3D movement for billboard levels.
+
+@export var move_speed: float = 6.0
+@export var attack_range: float = 1.8
+@export var attack_damage: int = 1
+
+signal interacted
+signal attacked
+
+@onready var _billboard: BillboardSprite = $BillboardSprite
+
+var _locked: bool = false
+
+func _ready() -> void:
+	add_to_group("player")
+	if _billboard and _billboard.texture == null:
+		var tex: Texture2D = load("res://assets/sprites/placeholders/player.png")
+		if tex:
+			_billboard.set_texture(tex)
+
+func _physics_process(_delta: float) -> void:
+	if _locked or get_tree().paused:
+		velocity = Vector3.ZERO
+		return
+	var input := Vector2(
+		Input.get_axis("move_left", "move_right"),
+		Input.get_axis("move_up", "move_down")
+	)
+	var dir := Vector3(input.x, 0.0, input.y)
+	if dir.length() > 1.0:
+		dir = dir.normalized()
+	velocity = dir * move_speed
+	move_and_slide()
+	if Input.is_action_just_pressed("interact"):
+		_try_interact()
+	if Input.is_action_just_pressed("attack"):
+		_try_attack()
+
+func lock_input(locked: bool) -> void:
+	_locked = locked
+
+func _try_interact() -> void:
+	interacted.emit()
+	for body in get_tree().get_nodes_in_group("interactable"):
+		if body is Node3D and global_position.distance_to(body.global_position) <= 2.2:
+			if body.has_method("on_interact"):
+				body.on_interact(self)
+				return
+
+func _try_attack() -> void:
+	attacked.emit()
+	AudioDirector.play_hit()
+	for body in get_tree().get_nodes_in_group("enemy"):
+		if body is Node3D and global_position.distance_to(body.global_position) <= attack_range:
+			if body.has_method("take_hit"):
+				body.take_hit(attack_damage)