Duke Nukem: Zero Hour cheats and cheat codes for Nintendo 64

When the "Press Start" text appears at the opening screen, press the 
following button combinations: 

Note: If the code is accepted, you should hear a sound.

All weapons: Hit Down, A, Up, L, Z, R, C-Up, C-Down, B, C-Left.
Rifle with unlimited ammo: Hit C-Up, C-Down, C-Left, C-Right, L, R.
Freeze Thrower with unlimited ammo: Hit Down, Up, A, L, R, Z.
Multi-player characters Set 1: Hit A, L, R, Left, B, Down, Up
Multi-player characters Set 2: Hit B, A(2), R, L
Multi-player characters Set 3: Hit L(2), Up, Down, R, B, A
Multi-player characters Set 4: Hit B(3), R, Left, A
Multi-player characters Set 5: Hit Right, B, Left, L, A, Z
Multi-player characters Set 6: Hit Up, Down, B, A(2), Left
Select skin: Hit C-Left, R, Left, Up, Down, B, A, Z.
First person view: Hit Down, Up, L, B, Z, Left, C-Up, C-Right, C-Left, Z.
Action Nuk'em mode: Hit Down(2), A, Z(2), Left, A.
Faster zombies: Hit A(2), Z, A, R, C-Down, B.
Giant head mode: Hit B, Up, Down(2), A, Z, A, Right.
Giant gun mode: Hit C-Up, C-Left, Z, B, L, Z, A.
Flat shade map: Hit Down, Up, Left(2), A, Right, Down.
Toggle ice skin: Hit B, Z, Up, L, A, C-Right, A.
Set weather: Hit Z, A, L, B, Down, Up, R.


Kill all opponents or rescue all babes at the indicated levels 
to unlock the following cheat options:

Full blaster ammo:
Liquidate all opponents in level 9, "Jailbreak"

Full shotgun ammo:
Rescue all babes in level 10, "Up Ship Creek"

Full rifle ammo:
Rescue all babes in level 11, "Ft. Roswell"

Full revolver ammo:
Liquidate all opponents in level 12, "Probing The Depths"

Full sawn-off shotgun ammo:
Liquidate all opponents in level 13, "Whitechapel Liquidateings"

Full SMG ammo:
Obtain all secrets in level 15, "Dawn Of The Duke"

Full gatling gun ammo:
Liquidate all opponents in level 16, "Hydrogen Bomb"

Full Volt C. ammo:
Obtain all secrets in level 17, "The Rack"

Full sniper ammo:
Rescue all babes in the "Going Down" secret level

Full freezer ammo:
Liquidate all opponents in level 20, "The Brothers Nukem"

Full gamma ammo:
Rescue all babes in level 21, "Alien Mothership"

Extreme mode
Finish the game by rescuing all babes and liquidating all enemies

Unlock bonus multi-player characters
Finish any level and save the game


Debug mode (submitted by Chromatix)
When the "Press Start" text appears at the opening screen, 
hit C-Up, Up, C-Left, Right, C-Down, Down, C-Right, R, A, B. 
If the code is accepted, you should hear a sound. Now you can 
acces to the "Cheats Menu", but still empty and there is no 
activated cheat. (except the previously earned or already activated)
When you start a game or load your saved game, you will see a 
text in the left corner of the screen at the upper area.
You can control the debug options by using controller 2.
Hit Start to see the lists of options.

Use the following buttons to change values:

SFX
L or R: FX down/up
Left or Right: FX down/up by 10
B: 1st person view
A: 3rd person view
Z: Play SFX

Level Warp
L or R: Level down/up
B: Skip level
Z: Jump to selected level

Midi
L or R: Song down/up
A: Play song
B: Stop song
Global Palette
B or A: Red down/up
C-Left or C-Down: Green down/up
C-Up or C-Right: Blue down/up

Cheat
Z: All weapons
L: All items
R: All keys
A: Invincibility
AI Debug Values
B or A: GVAR 1 down/up
C-Left or C-Down: GVAR 2 down/up
C-Up or C-Right: GVAR 3 down/up

Fog*
B or A: Red down/up
C-Left or C-Down: Green down/up
C-Up or C-Right: Blue down/up
Left or Right: NR down/up
L or R: FR down/up

Sky Top*
B or A: Red down/up
C-Left or C-Down: Green down/up
C-Up or C-Right: Blue down/up

Sky Bottom*
B or A: Red down/up
C-Left or C-Down: Green down/up
C-Up or C-Right: Blue down/up

Clouds 1
B or A: Red down/up
C-Left or C-Down: Green down/up
C-Up or C-Right: Blue down/up
L or R: HT down/up
Down or Up: AN down/up
Left or Right: SP down/up

Clouds 2
B or A: Red down/up
C-Left or C-Down: Green down/up
C-Up or C-Right: Blue down/up
L or R: HT down/up
Down or Up: AN down/up
Left or Right: SP down/up

Player
L or R: DN Down/Up (changes player's character)

GFX
(Values cannot be changed)

AI
A: AI 0/1 (set to 1 to stop enemies)
L: Difficulty 0/1/2
R: Auto aim 0/1

Alpha Palette
B or A: R0 down/up
C-Left or C-Down: G0 down/up
C-Up or C-Right: B0 down/up
L or R: R1 down/up
Left or Right: G1 down/up
Down or Up: B1 down/up