Human colonies are under attack! Defend your species against the aliens, create ships and earn experience to defeat the attacking forces. How long can you survive?
Every few seconds the action will pause, giving you the chance to use your mouse to create an additional ship to help defend your reactor. The reactor itself is equipped with a powerful cannon that you can aim with the mouse at the advancing enemies. You must protect the reactor at all costs, because the game will end when it is destroyed. However, every game played will reward you with experience points, which you can use to upgrade your ships and buy new ship designs.