What is "raycrisis"

RayCrisis, known as RayCrisis: Series Termination in North America, is the third game released in the "Ray" series of Taito shooting games. Chronologically, it is considered a prequel to the first game, RayForce. First released for arcades in 1998, it supported co-op mode for two players, which the PlayStation ports released in 2000 lack; these ports are the only games in the "Ray" series to lack co-op.