N20 - Nitrous Oxide

At the Main Menu Screen go to 'Game Options.' Now go to 'Enter Code' and, well, enter these codes!

Firewall Cheat:			X, X, Square, X, X, X, Triangle, Triangle
Weapons:			Square, X, O, Square, X, Square, O, Square
Infinite Lives:			O, X, X, Triangle, Square, Triangle, Square, O
Access Any Level:		Square, Triangle, O, Triangle, X, Triangle, Square, X
Bonus Level Access:		X, X, X, Square, Triangle, O, X, Triangle 
Water Effect:			O, X, Square, Triangle, Triangle, O, Triangle, O
No Bonus Reset after Death:	Square, Triangle, X, O, Square, Triangle, X
Disable Cheats:			Square, Square, X, O, O, O, O, Triangle

Game Shark Codes

Infinite Lives P1		8011b354 0103
				8011b36c 0103