A space robot strafes on a single row shooting at incoming aliens across a field of holes. The aliens duck in those holes to avoid the player's shots The space robot is damaged by aliens' projectiles, aliens' close range attacks or by hot ash spewing from the far volcanoes. The robot can jump to avoid some aliens that nearby.

A mechanic will attempt to replenish some of the robot's vitality. If the robot takes too many hits, a life is lost. If enough points are earned, the player is granted an extra life. A stage is complete when the whole wave of aliens is destroyed. The last stage requires the player to eliminate a boss alien, which completes the game level and the player proceeds to do the game again at a higher difficulty level.