Bangai-O is a multidirectional shooter developed by Treasure and released in 1999 on the Nintendo 64 in Japan. It was ported to the Dreamcast worldwide shortly after with some gameplay changes and updated graphics and audio. The game places the player in control of a weaponized mech that can hover across large stages and fire at enemies all around them. The player must reach the end of each stage and defeat the boss, while avoiding hazards scattered across the map such as enemy mechs and gun turrets.