Bangai-O (Japanese: Bakuretsu Muteki Bangaiō) is a multidirectional shooter developed by Treasure and published by ESP. First released in Japan on September 3, 1999 for the Nintendo 64, it was later ported to the Dreamcast for global release. It is a shoot 'em up (STG) with single-player support.
In the game, players control the armed mech Bangai-O, which can fly freely across vast levels and fire at enemies in all directions. The goal is to clear each level, defeat the final boss, and avoid hazards like enemy mechs and turrets scattered across the map. The game has drawn many shoot 'em up fans for its unique gameplay and high difficulty.
Notably, its sequel Bangai-O Spirits (Japanese: Bangaiō Tamashii) launched on the Nintendo DS on March 19, 2008. It retains the core gameplay of the original while adding new elements and improvements.