Enter all of these codes in the pause screen:
Invicibility:
L2,R1,L1,R2,Up,Down,Up,Down,SELECT,SELECT
All weapons:
L1,L2,Up,L1,L2,Down,R1,Right,R2,Left
Super Weapons:
R2,R1,L1,L2,R2,R1,L1,L2,SELECT,SELECT
All Items:
R1,R1,R1,R1,R1,L2,L2,L2,L2,L2
Level Select:
Down(9 times),up
Big-Head Duke:
R1(9 Times),down
Big-Head Enemies:
R1(9 Times),right
All Inventory:
R1(5 Times),L2(5 Times)
Double Duke:
L2,R2,L2,R2,L2,R2,L2,R2,L2,R2
All Keys:
Up,Right,Up,Left,Down,Up,Right,Left,Right,Down
Submitted By Team PowerGamerz