Doom

All weapons and armor:
Note: This code requires a six button controller. Press B + C + Y + Z during game play.

Invincibility:
Note: This code requires a six button controller. Pause game play and press X + Y + Mode + Up.

All weapons:
Note: This code requires a six button controller. Pause game play and press A + C + Mode + Up at the same time.

Invincibility, full health:
Note: This code requires a six button controller. Pause game play and press Up + Mode + X + Z.
Note: Game play may not progress past level 15 if this code is enabled.

All weapons, full ammunition, all keys:
Note: This code requires a six button controller. Pause game play and press A + B + C + X + Y + Z.
Note: Game play may not progress past level 15 if this code is enabled.

Weapon select:
Note: This code requires a six button controller. Press one of the following controller combinations to activate the corresponding weapon.

Weapon  Code
ChainsawMode + Start
PistolMode + A
ShotgunMode + B
ChaingunMode + C
Rocket LauncherMode + X
Plasma RiflesMode + Y
BFG 9000Mode + Z