Keyhack J toggle unlimited health, L unlock all levels.
Your mission in this futuristic fight for the survival of earth is to play as human and battle against Aliens, Robots, and Zombies. Or choose to be the bad guy and be the enemies and fight for the destruction of it.
Use WASD or ARROW KEYS to move around. Press SPACEBAR to jump. Use YOUR MOUSE to aim and shoot. Use 0-9 NUMBER KEYS (or "Q" and "E") to switch weapons. Check in-game How to Play/Tips section for more useful info. Good luck!