Cheat Mode:

At the "Press Start" screen, press Circle, Up, Up, Down, Down, Left, Right, Left, Right to unlock a "Bonus Match Up" option at the main menu. If you entered the code correctly, the words "Bonus Match Up" will appear at the top of the screen. The "Bonus Match Up" option allows you to play as any character and select any arena. Alternatively, successfully complete the new challenger, defender, and champion circuits.

Bonus Ring:

At the "Press Start" screen, press Circle, R2, R1, Circle, R2, R1 to unlock the Big Ape arena. If you entered the code correctly, you will hear a sound.

Big Arm Mode:

At the "Press Start" screen or after pausing the game, press Circle, L1, Circle, R1, Circle, L2, Circle. If you entered the code correctly, you will hear a sound.

Display Game Completion Date:

At the "Press Start" screen or after pausing the game, press Square, Circle, L1, R1. If you entered the code correctly, you will hear a sound.

Funny Credits:

At the "Press Start" screen, press Circle, L1, Circle, L1, Circle, R1, Circle, R1. If you entered the code correctly, you will hear a sound. Then, select the "Credits" option.

Unlock the Big Ape Arena:

At the Press Start screen, press Circle, R2, R1, Circle, R2, R1.

Unlock the Great Ones:

There are 4 different secret characters, moe, Bumble Bee man, Frink, and Ned Flanders. To get them you have to defeat them (ned is extremely hard! You must pin him twice to win the round. Cause god revives him.)

Unlock Itchy & Scratchy, Kang, And Smithers:

Beat the game in all 3 modes and you will unlock an option that enables you to play as Itchy & Scratchy for one level, Kang for another, and Smithers for yet another.

Beat Burns:

If you want to beat Mr. burns run into the side and press X so he can't get you but he might throw fish so try to dodge them.

Unlock Bonus Match Up:

Enter the following at the PRESS START screen: Circle, Up, Up, Down, Down, Left, Right, Left, Right.

Unlock the Mayor:

Press R1, R1, R1 then triangle. Now the screen will say do you want to save press yes. Now the next time you go to choose a player the mayor will be there. This cheat will only work while you are in a match.

The Homer Attack:

Pick Homer. Now when you have your invincibility ready. Get Homer to eat donuts (press 0). Right after he gets done activate your invincibility now pull out all your hits and just go crazy punching. When you do this the donuts increase Homer's attacks to big hits! Now that you can't die while you have invincibility Homer's best at close fighting so just tap!tap!tap!