On a research base, the geologists are being abducted while they work by aliens, and in this side view single screen shooter, it is your mission to destroy all the aliens while saving the scientists. You control a craft at the bottom of the screen, moving left or right, and you blast upwards to destroy various waves of aliens as they move around the screen dropping bombs. To save a scientist, you must shoot the alien that is holding him to save him. Other aliens appear on the surface and move across the screen and these need shooting as well because if you touch one or are hit by a bomb then you lose one of six lives.
