Mr. Do!'s Castle is a platform arcade game developed by Universal Co., Ltd and released in 1983. It's the sequel to the popular game 'Mr. Do!'. Players assume the role of the titular character, Mr. Do, who must climb ladders, dodge enemies, and use a hammer to knock out blocks in a castle setting. It distinguishes itself with its unique gameplay mechanics and strategic options, as players selectively clear blocks to either crush enemies or create paths. The game is remembered for its blend of puzzle elements with arcade action.