So your’re alone in a world that is invested by brain eating aliens. Marvelous! But what do you do? We figured the only logic thing that anyone would do in a situation like this, is shoot the purple crap out of them. The goal is to survive as long as possible form waves of enemies. As you progress you earn points by killing aliens. These points can be used to unlock various upgrades and new weapons, which you will need because enemies became tougher as you progress.