Doom II - Platform: Gameboy Advance
      
Press Start to pause the game, then hold L + R 
and enter one of the codes.

Code                     Result 
-------------------------------
A, A, B, A, A, A, A, A.  God mode 
A, B, B, A, A, A, A, A.  All weapons, items, keys 
B, A, A, A, A, A, A, A.  Computer map 
B, B, A, A, A, A, A, A.  Radiation suit 
B, B, B, A, A, A, A, A.  Invincibility 
B, A, B, A, A, A, A, A.  Berserk 
A, A, B, A, B, B, B, B.  Disable God mode