Destroy All Humans - God Mode

Unlimited Ammo:
Pause gameplay, then hold L2 and press Left, Circle, R2, Right, R1, Square.

Unlimited Mind:
Pause gameplay, then hold L2 and press R1, R2, Circle, Right, R2, Circle. Your MC meter will not decrease. Your current MC must be above zero for this code to work.

All Upgrades:
Pause gameplay, then hold L2 and press Square, Circle, Left, Left, Circle, Square while on the Mothership. All upgrades for the currently unlocked weapons will be available for purchase from Pox's lab.

Easter Egg:
On the mission 'Mr. Crypto goes to Capitol city', in the part where you have to go to the pentagon, you have to pass over a bridge and just before you cross the bridge there is a robot with a guard in front of it. when you go in front of the robot it says various things, but one of the things it says is 'Sarah Conner?'". This is a reference to Terminator 2.