Evil is trying to destroy the Zerg race Alliance of Men and Protos. Your main task is to prevent the Zerg in the Joint Staff. To do so, put the defense on the hill. Will start with very limited funds, which would hardly be enough for one defender robot. Destroying the enemy, you'll get the resources for which you can buy new combat vehicles and strengthen their defenses. The game perfectly executed, it is even a storyline that will intrigue you to the last mission.