"Bangai-O" received positive reviews for its initial Nintendo 64 release. Critics enjoyed the manic and unique gameplay that they believed was characteristic of Treasure's video games. Most compared it to older shoot 'em ups and action games. "GameFan" called it a mix between the free-floating gameplay of "Sub Terrania" (1994) and the rotating shooting action of "Omega Boost" (1999). They appreciated it as one of the few shooters on the Nintendo 64, and compared its aesthetic missile shooting style to "Macross". Peter Barthalow ("IGN") wrote that the game was "in typical Treasure fashion...an addictive and original hodgepodge of genres and game mechanics that defy easy explanation". Journalists commended the variety in the game's design that kept it feeling fresh throughout. Anoop Gantayat ("IGN)" wrote that the level design made good use of each character's shooting mode. Barthalow and Martin Kitts ("N64 Magazine") both praised the level design for forcing the player to change their tactics level to level. Barthalow called the building elements for the levels "versatile", and went on to say some levels were puzzles, others had racing aspects, and others were "insane blastfests". Gantayat argued that "Bangai-O" is "a game that you either love, or just don't understand yet".