Rampage: Total Destruction cheats and cheat codes for Gamecube

Cheat mode:
Press L2+R2 at the Main Menu to display the code entry screen. 
After enter one of the following codes

141421 - Unlock all monsters & stages
082864 - Unlock Demo mode with 2 random monsters 
000000 - Unfit all active codes 
314159 - Display game version 
874098 - Unlock Instant demo mode with 2 random monsters 
986960 - Invincible to military attacks 
071767 - One hit destroys a building 
667302 - Unlock View credits 
667301 - Unlock View ending theme 
667300 - Unlock View opening theme 
271828 - All stages
011235 - All special abilities
000020 - ?
249020 - ?

Unlock monsters:
Amanda the Armadillo - Los Angeles, play with Kyle 
Bart the Bat - Los Angeles, play with Kingston 
Cal the Squid - Los Angeles, play with Kyle 
Croc the Crocodile - Hong Kong, play with Rojo 
Edwin the Invader - London, play with Wally 
Harry the Yeti - Chicago, play with Marco 
Icky the Echidna - London, play with Ralph 
Jack the Jackelope - Las Vegas, play with Harry 
Jill the Jellyfish - Hong Kong, play with Amanda 
Joe the Wildman - New York, play with Natalie 
Kingston the King Cobra - Las Vegas, play with Lizzie 
Kyle the Cyclops - London, play with Kingston 
Leon the Lion - Las Vegas, play with Ralph 
Marco the Shark - San Francisco, play with Ralph 
Natalie the Nautiless - San Francisco, play with Marco 
Nick the Demon - Chicago, play with Harry 
Rocky the Granite man - New York, play with Cal 
Rojo the Bull - Chicago, play with Kyle 
Shelby the Turtle - San Francisco, play with Lizzie 
Venus the Plant - Hong Kong, play with Croc 
Wally the Warthog - New York, play with Marco 

Super-Unlockables:
Unlock Bubba - Unlock the other 23 of 29 bonus monsters
Unlock Eyegore - Win every challenge on every level in All Challenges Met
Unlock Philbert - Collect the PAR points for every level in Par Scores Met