First, enter the name GOURANGA to activate cheat mode. Now enter the following as your name before starting a level:

MUCHCASH        Start with $500,000 (save, exit, then restart your game)
GODOFGTA        All weapons, full ammo   
GOREFEST        More gore   
EATSOUP         Free shopping
BUCKFAST	More aggressive peds
RSJABBER 	God mode
CUTIE1          99 lives
ARSESTAR        Keep weapons after you die
FLAMEON         Gives you a flamethrower
VOLTFEST        Gives you electricity ray gun
IAMDAVEJ        Gives you $9,999,999
TUMYFROG        Gives you all of the bonus levels
SCHURULZ        Double damage powerup
HUNSRUS         Invisible
UKGAMER         Gives you all 3 cities
BEMEALL         Gives you all 3 cities
DANISGOD        Gives you $200,000
MADEMAN         Get all respect from 3 gangs
LASVEGAS        Some people turn to "Elvis clan"
NEKKID          All people naked
FISHFLAP        Makes all cars small

Hints

Thanks to Revolution readers 0akley, ICE, Masis, CheeseWeesel, Vincent Witzel, Utopia Parkway, Scotty, Chay Curtin, Adam Whittaker, Tha Esp, Chad, Matthew Heap, GusGus, MIDI-Man, Charlie, Oz, Ville Kotro, Sir Edward Figaro, Chris, Michael, Antonin Grele and The Angel!