Door Door

Door Door is a single-screen puzzle-platformer where players control Chun, a small egg-shaped creature wearing a baseball cap. Players must open sliding doors to trap a quartet of pursuing aliens (Namegon, Amechan, Invekun, and Otapyon) that chase Chun using deterministic algorithms and ladders. Once an alien enters a door, it must be closed to permanently remove it from the level. Each stage features platforms, ladders, and doors in a single-screen layout. The game mode is single-player with 50 levels total. Chun is relentlessly pursued by the aliens, making timing and positioning critical to survival. What makes it stand out is its elegant, non-standard puzzle design and viral fame as Enix's debut Famicom game.