During play, select the Electro-Cosh at the weapon selection screen and enter the following:

Invincibility:
L, R, L, R, A, B, B, A, X, Y

Unlimited ammunition:
L, R, L, R, A, B, B, A, X, X

Level skip:
L, R, L, R, A, A, B, B, X, B

Level select:
L, R, L, R, A, A, B, B, X, X

Double damage:
L, R, L, R, A, B, B, A, Y, Y

One hit kills:
L, R, L, R, A, B, B,, A, A, A

Auto-focus on enemies:
L, R, L, R, A, B, B, A, B, A

Big heads:
L, R, L, R, A, B, B, A, B, B

Floating camera view:
L, R, L, R, A, B, B, A, Y, X

Thanks to Revolution reader Marked For Life!