Your mission in this top down shooter is to fight these head crabs. Use YOUR MOUSE to aim and shoot. Use WASD KEYS to move around. G KEY will throw grenades, and F KEY is kick attack. Press R KEY to reload. Use 1-4 KEYS to change weapon. Hold SHIFT to sprint and press SPACEBAR for bullet time. As you use each weapon you will gain skill, for example rate of fire and accuracy will increase. By the 5th level there are lots of different enemies making it quite a tough challenge. Good luck!