Destroy the alien ships while avoiding getting hit yourself! Choose either the mouse or keys option after you click play. In the mouse option, you simply move the mouse around to move your ship, and click the left button to fire your shockwave. In the keys option, you steer your ship with either the arrow or WASD keys, and hit M to fire your shockwave. Your ship fires its guns automatically, but shockwave is much more effective at destroying the enemies. However, you can only use the shockwave when the blue bar in bottom left corner is filled.