There is a huge metal complex inside an asteroid that houses and guards a two-headed alien called Garth. Garth just wants to destroy Earth. Earth isn't going to put up with this so the player character is sent to destroy four power units that give Garth his energy. To do this he has to collect flasks, fill them up with acid, locate a power unit and blow it up. Trying to stop the protagonist are Garth's minions. The hero has a limited shield and limited lasers, which can be topped up.

Metaplex is viewed from the side. It is a maze game where one room is shown at a time. The player character rides in a space-type buggy. The screen shows the player a lot of information including lives, flasks, how much shields and lasers the hero has, score, and of course the main playing area.