Instructions
Begin a game under any difficulty setting.
Enter the cheat code during regular gameplay. For example, if you wanted Wolverine to be invulnerable you would enter "Square," "X", "X," "Square," "Triangle," "Triangle," "Square," "Circle," "Circle," "Square" and "R3."
Listen for a sound to indicate that the code has been entered correctly. You will hear a beeping sound if the code was entered correctly. If you entered the invulnerability code, you can also play the game for a few minutes to see if the code worked. If you lose health but don't die, then the code was effective.