Beat the Game
While playing hold L2 + R2 then press Square, Triangle, Circle, Circle, Start.
Small Head Opponents
Press R1(9), Right
Big Head Opponents
Press R1(9), Left
Small Head Duke
Press R1(9), Down.
Big Head Duke
Press R1(9), Up
Double Damage
Press L2, R2, L2, R2, L2, R2, L2, R2, L2, R2.
Infinite Ammo
Press [Left, Right, Left, Right, Select] twice.
Invisibility
Press L1, R1, L1, R1, L1, R1, L1, R1, L1, R1.
Temporary Invincibility
Press R1, L2, L1, L2, R1, L1, R1, L2, L1, L2.
Invincibility
Press L2, R1, L1, R2, Up, Down, Up, Down, Select(2).
All Keys
Press Up, Right, Up, Left, Down, Up, Right, Left, Right, Down.
All Items
Press R1(5), L2(5).
All Weapons
Press L1, L2, Up, L1, L2, Down, R1, Right, R2, Left.
Select Powered-Up Weapons
Press Right(2), Left, Right(2), Left, Right(2), Left.
Level Select
Press Down(9), Up {See Note Below} Note: After entering this code, exit the game. Then at the bottom of the main menu there will be a new option called "Time To Kill". Select this new option, then press Left or Right to choose a level and press X to go to the level.
Invulnerability
Enter one of the following codes while the game is paused:
First pause the game and press: L2, R1, L1, R2, UP, DOWN, UP, DOWN, SELECT, SELECT. And it should say Invulnerability.
View Scenes
Intro Scene: Pause game, press select, up nine times, select, L1.
Victory Scene: Pause game, Select, up nine times, select, L2.
View Credits: Pause game, Select, up nine times, select, R1.
Make Duke Wear A Kilt:Pause game, Select, up nine times, select, R2