Unlock Everything PS2
The PlayStation 2 version of the game has a cheat to unlock all the hidden characters and every costume for each character. To activate the cheat, you must go to the game's main menu. Hold down "L1," then press "Right," "Right," "Left," "Left," "Down," "Up" and "Circle" to activate the cheat. You will see a message stating that all characters and costumes are unlocked if you did this correctly.
Unlock Everything Xbox
The Xbox version of the game also has the unlock everything cheat, but the button sequence is different. As with the PS2 version, you must be at the main menu to enter this cheat. Hold down "L1," then press "Right," "Right," "Left," "Left," "Down," "Up" and "B" to activate this cheat. You will see a message if you entered the cheat correctly.
Unlock Everything GameCube
As with the PS2 and Xbox versions of the game, the GameCube version has an unlock everything cheat. Due to the button names and placement, the sequence for this version of the game is the same as the Xbox version. Hold "L1," then press "Right," "Right," "Left," "Left," "Down," "Up" and "B" at the main menu to activate the cheat.
Additional GameCube Cheats
In addition to the unlock everything cheat, the GameCube version of the game has additional cheats that make the game easier.
Press "Up," "Up," "Down," "Down," "A," "A," "B," "B," "X," "X," "Y" and "Y" at the main menu to turn off the enemies' artificial intelligence.
Press "Up," "Up," "Down," "Down," "A," "X," "A" and "X" at the main menu to have infinite Super Moves.
Press "Up," "Up," "Down," "Down," "X," "Y," "Y" and "X" at the main menu to activate the one-hit kill cheat. This cheat allows you to kill every enemy with a single attack.
Re-enter any of these cheats at the main menu to deactivate them.