The main section of each level takes place above the surface of one of the lifeless planets, and plays like a Defender-style shoot-'em-up. The Star Breaker can fly in four directions as it tracks down the Rrampon forces on its radar display - from mines and suicide droids to the dreaded Harvester command ships. The docking bays on the surface provide access to the underground bases. Here, control is transferred to the Light Trooper android, which heads down to the tunnels to hunt down the overlords and their Space Clams. The android can either fly through the rooms using its thrusters, or walk on the ground; computer terminals provide status reports, and can resupply the player with ammo, shields, thruster power and bombs.