Pause the game and enter these codes at a slow but even pace. If you enter these codes to fast they may not work.

Infinite Ammo- Left, right, left, right, select, left, right, left, right, select

All Weapons- L1, L2, up, L1, L2, down, R1, right, R2, left

All Inventory- R1, R1, R1, R1, R1, L2, L2, L2, L2, L2

All Keys- up, right, up, left, down, up, right, left, right, down Invisible- L1, R1, L1, R1, L1, R1, L1, R1, L1, R1

Invincibility- L2, R1, L1, R2, up, down, up, down, select, select,

Double Damage- L2, R2, L2, R2, L2, R2, L2, R2, L2, R2

Temporary Invulnerability- R1, L2, L1, L2, R1, L1, R1, L2, L1, L2 Big

Head Duke- R1, R1, R1, R1, R1, R1, R1, R1, R1, up

Little Head Duke- right, R1, R1, R1, R1, R1, R1, R1, R1, down

Big Head Enemies- R1, R1, R1, R1, R1, R1, R1, R1, R1, left

Little Head Enemies- R1, R1, R1, R1, R1, R1, R1, R1, R1, right

While playing pause the game and press down 9 times and then press up and it should say level select. Now quit the game and on the main menu you will see a new option that says "Time To Kill". Select it and press right or left to choose the level that you want to go to. Press X on to play the level.

Turn on the game. When the GT Interactive logo appears simultaneously press R1+R2+L1+L2.