Rampage: Total Destruction Cheats for GameCube

Hold R and L at the main Menu screen then type the following codes
141421 - Unlock All Monsters
000000 - Deactivates all active codes
986960 - Invincible to all Military Attacks(Bombers,Infintry,Tanks,etc.)
071767 - One hit Destruction(Buildings only)
667300 - View Opening Theme
667301 - View Ending Theme
667302 - View Credits

Unlock Special Monsters
Complete the Special Star Challenges in the cities to unlock the corresponding monster.
Unlock Eyegore:
Complete ALL the Challenge Stars in ALL the cities

Unlock Philbert:
Complete ALL the Par Point Stars in ALL the cities
Unlock Bubba:
Unlock ALL the secret monsters including Philbert and Eyegore.

Unlockable Monsters
The following mosters in the cities listed below are used to unlock the other monsters. It is poosible that there may be more then one monster to unlock the secret ones. And you might have to re-do the city to unlock the other ones that are in it.
Unlock Amanda:
Play as Kyle in Los Angeles
Unlock Bart:
Play as Kingston in Los Angeles