Your job is to protect the eponymous Colony 7, a space colony in a typically volatile galaxy, from the evil Jarvians’ squadrons. You have unlimited ammunition for your fixed cannons and three power cells for special attacks. Each cell can trigger a “mega blaster” -- or you can use all three cells at once for an omni-powerful blast from the “eradicator”. Whatever you do, protect your cannons and your force field, because Colony 7 becomes an easy target once your defenses are gone.