Godzilla: Destroy All Monsters Melee Codes - 
  Cheat mode:
 Press and hold 
 +
 + 
 +
 + 
 (in that order) in the main
  menu, then depress and release
 (in that order) in the main
  menu, then depress and release 
 ,
, 
 ,
, 
 (in that order) to
  see the
  code entry screen.
 (in that order) to
  see the
  code entry screen.
            
Every city and monster:
Submit the code 863768
            . You will hear a monster if you have entered the code correctly. 
            
Unlock Godzilla 2000:
Submit the code
            637522  . You will hear a monster if you have entered the code correctly.
            Or finish adventure mode as Godzilla
            90s version.
            
Unlock King Ghidorah:
Submit the code
            939376  . You will hear a monster if you have entered the code correctly.
            Or finish adventure mode as Megalon.
            
Unlock Rodan:
Submit the code
            724284  . You will hear a monster if you have entered the code correctly.
            Or finish adventure mode as Gigan.
            
Unlock Destoroyah:
Submit the code
            352117  . You will hear a monster if you have entered the code correctly.
            Or finish adventure mode as Godzilla
            2000.
            
Unlock Mecha King Ghidorah:
Submit the code 504330
            . You will hear a monster if you have entered the code correctly. Or finish
            adventure mode with King Ghidrah.
            
Unlock Mecha
            Godzilla:
Submit the code 643861  . You will hear a monster if you have entered the code correctly.
            Or finish adventure mode as Destoroyah, Rodan and Mecha King Ghidrah.
            
Unlock Orga:
Submit the code
            622600  . You will hear a monster if you have entered the code correctly. 
            
All monsters except Orga:
Submit the code 753079
            . You will hear a monster if you have entered the code correctly.
            
All monsters:
Submit the code
            209697  . You will hear a monster if you have entered the code correctly.
            
Monster Island level:
Submit the code
            745749  . You will hear a monster if you have entered the code correctly.
            
Mothership level:
Submit the code
            972094  . You will hear a monster if you have entered the code correctly.
            Or finish adventure mode as Mecha
            Godzilla.
            
Boxing ring level:
Submit the code
            440499  . You will hear a monster if you have entered the code correctly.
            
All cities:
Submit the code
            107504  . You will hear a monster if you have entered the code correctly.
            
Player one is small:
Submit the code
            558277  . You will hear a monster if you have entered the code correctly.
            
Even numbered players are
            small:
Submit the code 600095  . You will hear a monster if you have entered the code correctly.
            
Player two is small:
Submit the code
            689490  . You will hear a monster if you have entered the code correctly.
            
Odd numbered players are
            small:
Submit the code 853955  . You will hear a monster if you have entered the code correctly.
            
Player three is small:
Submit the code
            203783  . You will hear a monster if you have entered the code correctly.
            
Player four is small:
Submit the code
            495355  . You will hear a monster if you have entered the code correctly.
            
All players are small:
Submit the code
            154974  . You will hear a monster if you have entered the code correctly.
            
Add AI player to Melee (human versus AI):
            
Submit the code 154974  . You will hear a monster if you have entered the code correctly.
            
Ending credits and play Godzilla March
            Theme:
Submit the code 339223  . You will hear a monster if you have entered the code correctly.
            
All gallery items:
Submit the code
            962129  . You will hear a monster if you have entered the code correctly.
            
Player one takes no
            damage:
Submit the code 152446  . You will hear a monster if you have entered the code correctly.
            
Player two takes no
            damage:
Submit the code 724689  . You will hear a monster if you have entered the code correctly.
            
Player three takes no
            damage:
Submit the code 367744  . You will hear a monster if you have entered the code correctly.
            
Player four takes no
            damage:
Submit the code 317320  . You will hear a monster if you have entered the code correctly.
            
All players take no
            damage:
Submit the code 569428  . You will hear a monster if you have entered the code correctly.
            
Player one deals quadruple
            damage:
Submit the code 940478  . You will hear a monster if you have entered the code correctly.
            
Player two deals quadruple
            damage:
Submit the code 930041  . You will hear a monster if you have entered the code correctly.
            
Player three deals quadruple
            damage:
Submit the code 537651  . You will hear a monster if you have entered the code correctly.
            
Player four deals quadruple
            damage:
Submit the code 889610  . You will hear a monster if you have entered the code correctly.
            
All players deal quadruple
            damage:
Submit the code 817683  . You will hear a monster if you have entered the code correctly.
            
Military deals quadruple
            damage:
Submit the code 970432  . You will hear a monster if you have entered the code correctly.
            
Disable HUD:
Submit the code
            880460  . You will hear a monster if you have entered the code correctly.
            
Players health
            regenerates:
Submit the code 597378  . You will hear a monster if you have entered the code correctly.
            
Throw all buildings and
            objects:
Submit the code 248165  . You will hear a monster if you have entered the code correctly.
            
Indestructible
            buildings:
Submit the code 451129  . You will hear a monster if you have entered the code correctly.
            
Hedorah (Smog Monster) in every
            game:
Submit the code 288730  . You will hear a monster if you have entered the code correctly.
            
No Hedorah (Smog
            Monster):
Submit the code 584408  . You will hear a monster if you have entered the code correctly.
            
Player one invisible:
Submit the code
            659672  . You will hear a monster if you have entered the code correctly.
            
Player two invisible:
Submit the code
            493946  . You will hear a monster if you have entered the code correctly.
            
All monsters
            invisible:
Submit the code 600225  . You will hear a monster if you have entered the code correctly.
            
Energy does not recharge, but energy
            weapons do more damage.:
Submit the code 690242  . You will hear a monster if you have entered the code correctly.
            
Toggle military:
Submit the code
            728629  . You will hear a monster if you have entered the code correctly.
            
Player indicators always
            visible:
Submit the code 860068  . You will hear a monster if you have entered the code correctly.
            
Constant full energy for player
            one:
Submit the code 778393  . You will hear a monster if you have entered the code correctly.
            
Constant full energy for player
            two:
Submit the code 881557  . You will hear a monster if you have entered the code correctly.
            
Constant full energy for player three:
            
Submit the code 597558  . You will hear a monster if you have entered the code correctly.
            
Constant full energy for pplayer four:
            
Submit the code 218967  . You will hear a monster if you have entered the code correctly.
            
No health power-ups:
Submit the code
            221086  . You will hear a monster if you have entered the code correctly.
            
No Mothra power-ups:
Submit the code
            491040  . You will hear a monster if you have entered the code correctly.
            
No energy power-ups:
Submit the code
            803358  . You will hear a monster if you have entered the code correctly.
            
No rage power-ups:
Submit the code
            666500  . You will hear a monster if you have entered the code correctly.
            
No freeze tanks:
Submit the code
            223501  . You will hear a monster if you have entered the code correctly.
            
No power-ups:
Submit the code
            229497  . You will hear a monster if you have entered the code correctly.
            
No power-ups except
            Energy:
Submit the code 553945  . You will hear a monster if you have entered the code correctly.
            
No power-ups except
            Rage:
Submit the code 660398  . You will hear a monster if you have entered the code correctly.
            
No power-ups except
            Health:
Submit the code 270426  . You will hear a monster if you have entered the code correctly.
            
Player one always in
            Rage:
Submit the code 159120  . You will hear a monster if you have entered the code correctly.
            
Player two always in
            Rage:
Submit the code 491089  . You will hear a monster if you have entered the code correctly.
            
Player three always in
            Rage:
Submit the code 450514  . You will hear a monster if you have entered the code correctly.
            
Player four always in
            Rage:
Submit the code 702905  . You will hear a monster if you have entered the code correctly.
            
Black and white mode:
Submit the code
            860475  . You will hear a monster if you have entered the code correctly.
            
Technicolor mode:
Submit the code
            394804  . You will hear a monster if you have entered the code correctly.
            
Twelve continues in adventure
            mode:
Submit the code 548319  . You will hear a monster if you have entered the code correctly.
            
Display game version number at option
            menu: 
Submit the code 097401  . You will hear a monster if you have entered the code correctly.
  
Unlock Godzilla 2000:
 Submit the code 637522  .  .