Mr. Do!'s Castle

Mr. Do!'s Castle is a 1983 arcade platformer where you defend a multi-story brick structure from invading unicorns. You control Mr. Do! with a hammer, navigating floors connected by ladders while enemies patrol the maze. Combat works two ways: whack unicorns directly or knock out floor blocks to drop them through gaps. The goal is collecting keys spread across each level—grab them all to clear the stage. Timing matters since removed blocks create new pathways for both you and enemies. You can also trigger chain reactions by collapsing multiple floors at once. Levels get tighter as unicorn counts rise and safe routes shrink. Good for players who like spatial puzzles mixed with reflex challenges.