Destroy all enemy units and stay alive as long as you can. Collect the coins to upgrade your skills and try to reach the safe zone of each level to proceed. When you start the campaign mode, you can edit attributes and you may play different characters. There is also a survival mode where you are swarmed with millions of cyborgs. It does have a good atmosphere and it has a lot of nice features.
WASD to move, MOUSE to aim, LEFT MOUSE BUTTON to attack.