Enter 760611 as a code. A monster will roar to confirm correct code entry.
Almost all monsters
Enter 696924 as a code. A monster will roar to confirm correct code entry. All monsters except for Orga will be unlocked.
Black and white mode
Enter 567980 as a code. A monster will roar to confirm correct code entry.
Cheat mode
Hold L + B + R (in that order) at the main menu, then release B, R, L (in that order) to display the code entry screen.
Disable life and energy display
Enter 443253 as a code. A monster will roar to confirm correct code entry.
Easy Kills on Adventure Mode
Use Godzilla 2000 or 90's and enter the unlimited energy cheat. Then, use atomic fireball over and over again. It will kill all the monsters, even Mecagodzilla.
Indestructible buildings
Enter 112122 as a code. A monster will roar to confirm correct code entry.
Invisible player two
Enter 459113 as a code. A monster will roar to confirm correct code entry.
Make baby monsters
Enter: small player 1 or 2 cheat. Then choose any monster. The monster you choose will be just the right size to be a baby. Note: the monster you choose won't be an actual baby. For example: if you choose Godzilla 90's, the guy who says monster names won't say "Minilla" or "Godzilla JR.".He'll say "Godzilla 90's" instead.
No energy gain for player one
Enter 650867 as a code. A monster will roar to confirm correct code entry.
Play as Orga
At the main menu, Hold L,B,R in that order. Release them in this order: B,R,L. Then enter this as a code-202412.
Small player one
Enter 986875 as a code. A monster will roar to confirm correct code entry.
Small player two
Enter 971934 as a code. A monster will roar to confirm correct code entry.
Technicolor mode
Enter 661334 as a code. A monster will roar to confirm correct code entry.
Unlimited health for player one
Enter 677251 as a code. A monster will roar to confirm correct code entry.
Unlock Mecha Godzilla
Beat the game with Destroyah, Rodan, and Mecha Ghidora.
Unlock monsters
The other way to unlock monsters is to beat the game with certain characters.
Winning With - Unlocks
Godzilla '90s - Godzilla 2000
Godzilla 2000 - Destroyah
Anguirus - Gigan
Gigan - Rodan
Megalon - King Ghidorah
King Ghidorah - Mecha King Ghidorah
Unlock Orga
Beat the game with all characters.
Unlock Space Godzilla
Beat the game with all characters and Orga twice on hard. The second time you beat it with Orga, instead of facing Meca-Godzilla, you face Space Godzilla. (The random ? turns into Space Godzilla when you get him.)
View credits
Enter 176542 as a code. A monster will roar to confirm correct code entry.
View version number
Enter 097401 as a code. A monster will roar to confirm correct code entry.