Destroy All Humans!

Pause game play, then hold L2 and press Square, Circle, Left(2), Circle, Square while on the Mothership. All upgrades for the currently unlocked weapons will be available for purchase from Pox's lab.

Every chance you get, do not kill the human before you extract their brain stem. Extract their brain stem first as it will make the DNA worth more (25 instead of 10).The easiest humans to do this to are the scientists in the level with glowing cows. For some reason, if the person that is important to you dies (the person you need to abduct), extract their brain stem before you return to the Mothership -- the DNA is usually worth more.

On the mother ship hold L2 and press R1, R1, R2, R2, Left, Right, Left, Right, R2, R1. This gives you extra DNA.

Shoot the tires of any vehicle with the zap-o-matic instead of the main vehicle body and their health goes down faster.

Hold L2, enter cheat, then release L2.

Invinciblity
Square, circle, left of d-pad, left on d-pad, circle, square

Infinite Ammo
left on d-pad, circle, R2, right on d-pad, R1, square

Infinite Mind
R1, R2, circle, right on d-pad, R2, circle

Aware Like A Fox
Right, Square, R2, R1, Right, R2

Nobody Loves You
Right, R2, R1, Square, Right

Mmmm Brains! (Must be entered on Mothership)
R1, R1, R2, R2, Left, Right, Left, Right, R2

More Upgrades (Must be entered on Mothership)
Square, Circle, Left, Left, Circle, Square

Instead of holding R to destroy buildings or large objects, tap R1 and the destruction will happen faster without waiting for the recharge.

Probes are necessary to get upgrades faster. In order to find them all, make sure to look high up on rocks or hard to reach places. Your jetpack is essential in getting to the high places. You may have to get up on the ledge or building, then use your jetpack to fly higher to get the probe.

Forget running away from the authorities with short legs. Use your jetpack liberally to fly away. Press Left Analog-stick Forward and hold X to boost away.

Put your target (dot in the middle of the screen) on any human, and press Circle. In order to maintain your HoloBob, you must read the thoughts of the humans walking around. You can read the same person's thoughts repeatedly to keep your mental powers charged.

It you levitate a person for a long time, they will die.