While at the Password Screen, type in the codes listed to unlock the corresponding cheat:
 

Cheat	Password
God Mode	Down, Left, L1, Left, Right
Unlimited Specials	Triangle, L1, Down, Triangle, Up.
Stronger Specials	Up, Start, Circle, R1, Left
Faster Weapon Shots	R1, L1, Down, Start, Down
Health's Regenerate Quicker	Triangle, L1, Down, Triangle, Up
CPU's Ignore Health	L1, Left, Right, Circle, Right
CPU's only attack Players	Right, Triangle, Right, Triangle, R1
2 Players vs. 1 CPU Ally	Down, Down, Right, Right, Down
Slick Playing Fields	Down, Triangle, Down, L1, R1
No Weapon/ Health Pick-ups	Circle, Start, Left, L1, Start
No Health in Deathmatch	Triangle, Down, Triangle, Circle, Triangle
No Health	Down, R1, Down, Start, Circle
Unlock Extra Deathmatch Levels	Beat each tournament and save.

Unlock Bosses

Beat the game and save

Unlock Bosses with Passwords

Type in the corresponding code at the Password Menu to unlock the boss.

Boss	Code
Crusher	Down, R1, Right, R1, L1
Moon Buggy	Start, Triangle, Right, L1, Start
RC Car	Up, Down, Left, Start, Right
Super Auger	Left, Circle, Triangle, Right, Down
Super Axel	Up, Right, Down, Up, L1
Super Slamm	Right, L1, Start, Circle, Start
Super Thumper	Circle, Triangle, Start, Circle, Left
Minion	Triangle, L1, L1, Left, Up
Sweet Tooth	Start, R1, Right, Right, Left

Choose Level

Type in the corresponding code at the Password Menu to start at the chosen level.

Level	Code
Neon City	Left, Triangle, Right, Right, Left
Road Rage	Start, Start, Down, Circle, L1
Bedroom	L1, Right, Left, Left, L1
Amazonia 3000 BC	Circle, L1, Start, L1, Start
Oil Rig	Start, Left, Up, Start, Circle
Minion's Maze	Start, R1, Left, R1, R1
The Carnival	Circle, Left, Down, R1, L1

Choose Weapon Pick-Ups

Type in the corresponding code at the Password Menu to make all pick-ups that weapon.

Weapon	Code
Power Missile	Down, Down, Circle, L1, Left
Homing Missiles	R1, Right, Left, R1, Up
Napalms	Right, Left, R1, Right, Circle
Remote Bombs	Up, Right, Down, L1, Triangle

Special moves

During game play, type in the D-Pad motions given to unlock the corresponding Move:

Move	Motion
Freeze	Left, Right, Up(2)
Rear freeze	Left, Right, Down(2)
Massive attack	Up, Down, Up, Down, Up
Rear massive attack	Up, Down, Up, Down(2)
Rear attack	Right, Left, Down(2)
Jump	Up(2), Left
Shield	Up(2), Right
Invisibility	Down(2), Up(2)
Hyperspace	Up(2), Down(2)