Aim of the game - you must maneuver your ship through alien territory, gaining points by hitting the various targets with bombs or missiles. Your final objective is to destroy the mothership in Level 7 with an accurately placed bomb. Levels 1 through 7 are then repeated, but become more difficult. Various hazards are encountered during the missions. Rockets fire up from the ground, UFOs bounce up and down and meteors shoot across the screen. If you run out of fuel, you perish. However, you can replenish your fuel supply by destroying the fuel depots along the way.