El sistema más potente de combate de la galaxia está en marcha.
El que se autodenomina como hombre "más excelente de todos", Riki, y su hermana menor, "tranquila pero espabilada", Mami, tienen que proteger al Manstar Vortex, en cuya obtención ha puesto gran interés la pandilla cósmica SF.
An interstellar crime syndicate is financing their nefarious schemes by smuggling space fruits throughout the galaxy. You take the role of Riki and Mami, two members of an elite force sent to stop the illegal activities. Your task is to get into the powerful Bangai-O suit, infiltrate the syndicate's bases, and confiscate the fruit. Naturally, the gangsters will not sit by and let you do this; you will have to take out swarms of enemies along the way. Luckily, the suit has two different firing modes that you can choose from: homing missiles and reflecting laser shots. When the going gets tough, you can also use the super bomb, which destroys every foe on the screen. You are also free to move around the environment, and you can fire in any direction. All of the action takes place in more than 40 levels that will put your fruit-busting skills to the test. Only you can protect the galaxy from the perils of bad fruit in Bangai-O.