The Zylons have returned to attack the Celos IV star system. In this 3D shoot-'em-up, the player takes control of the Liberty Star and must warp to threatened planets to battle the Zylon Fly Fighters and Destroyers. The Zylon Squadrons can also be attacked while in transit, and friendly Space Stations allow refueling. To achieve victory, the Zylon Attack Bases on their own planets must be destroyed. The game ends if the Liberty Star runs out of fuel, or if all cities are destroyed by Zylons.