Duke Nukem 64

NTSC version cheats:

Enable cheat mode:
Go to the main menu and press the following button combination:
Left, Left, L, L, Right, Right, Left, Left

Unlock all items:
Enable the Cheat mode, then go to the main menu and press the
following button combination:
R, C-Right, Right, L, C-Left , Left, C-Right, Right

Invincibility:
Enable the Cheat mode, then go to the main menu and press the
following button combination: R(7 times), Left

Stage select:
Enable the Cheat mode, then go to the main menu and press the
following button combination:
L(3 times), C-Right, Right, Left, Left, C-Left

Disable monsters:
Enable the Cheat mode, then go to the main menu and press the
following button combination:
L, C-Left, Left, R, C-Right, Right, Left, Left, Right

Infinite jet pack fuel:
While flying with the jet pack, use unlock all items cheat.


PAL version cheats:

Enable cheat mode:
Go to the main menu and press the following button combination:
Left, Down, L, L, Up, Right, Left, Up.

Unlock all items:
Enable the Cheat mode, then go to the main menu and press the
following button combination:
R, C-Right, Down, L, C-Up, Left, C-Right, Left.

Invincibility:
Enable the Cheat mode, then go to the main menu and press the
following button combination: R, C-Right, R, L, R(3 times), Left.

Stage select:
Enable the Cheat mode, then go to the main menu and press the
following button combination: R, L, R, C-Down, Right, Up, Left, C-Up.

Disable monsters:
Enable the Cheat mode, then go to the main menu and press the
following button combination:
L, C-Up, Left, L, C-Down, R, L, R.