All Items Pause and press R1 (5x), L2 (5x).

All Keys Pause and press Up, >, Up, <, Down, Up, >, <, >, Down.

All Weapons Pause and press L1, L2, Up, L1, L2, Down, R1, >, R2, <.

Big Head Duke Pause and press R1 (9x), Up.

Big Head Enemies Pause and press R1 (9x), L1.

Credits Pause and press Select, Up (9x), Select, R1.

Double Damage Pause and press L2, R2, L2, R2, L2, R2, L2, R2, L2, R2.

Ending Pause and press Select, Up (9x), Select, L2.

Game Completed During gameplay, press and hold L2+R2 and press Square, Triangle, Circle, Circle, Start.

Infinite Ammo Pause and press <, >, <, >, Select, <, >, <, >, Select.

Infinite Continues Pause and press <, >, Up, <, >, Down, <, >, L1, R1.

Intro Sequence Pause and press Select, Up (9x), Select, L1.

Invincibility Pause and press L2, R1, L1, R2, Up, Down, Up, Down, Select, Select.

Invisibility Pause and press L1, R1, L1, R1, L1, R1, L1, R1, L1, R1.

Kilt Sequence Pause and press Select, Up (9x), Select, R2.

Level Select Pause and press Down (9x), Up. Then, quit the game, go to the main menu, choose your level with < or >, and press X.

Rogue Trip Video At the GT screen, press and hold L1+L2+R1+R2.

Temporary Invulnerability Pause and press R1, L2, L1, L2, R1, L1, R1, L2, L1, L2.

Tiny Head Duke Pause and press R1 (9x), Down.

Tiny Head Enemies Pause and press R1 (9x), >, or pause and press R1, R1, R1, L1, L1, L1, R2, R2, R2, >.

(Note: enter the codes where you need to pause at a slow and even pace--don't enter them too fast.)