Go to the password screen in options and type in L1, left, right, circle, right as your password.
CPU Only Shoots at Player 1
Password: Right, Triangle, Right, Triangle, L1
Invincibility
Go to the options menu and go to "password" and enter Down, Left, L1, Left, Right. You should hear sweet tooth's laugh to confirm.
Play as all the bosses
Enter any of these passwords at the password screen:
Sweet Tooth: start, R1, right, right, left
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, triangle
Super Axel: up, right, down, up, L1
Minion: triangle, L1, L1, left, up
Super Thumper: circle, triangle, start, circle, left
Super Slamm: right, L1, start, circle, start
You should now have the vehicles that you entered at the password screen!
Special moves
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)
Tips for beating Sweettooth
First of all never engage Sweetooth when he is facing you because he will use his special every time. You can defeat Sweetooth easily by using proximity mines inside the Haunted House. And stay on the move at all times. If you get caught in one of Sweettooth's specials then use your shield.
Unlimited Special Weapons
Password: Triangle, L1, Down, Triangle, Up
Unlock All Secret Characters/Levels
For every level you beat in Tournament, you will unlock a secret Deathmatch-only level. Beat the complete game once and you'll unlock all the secret characters: Sweet Tooth, Moon Buggy, Super Thumper, Super Axel, Super Auger, Super Slam, RC Car, Minion, and Crusher.