Big Head Mode
To enable Big Head Mode, make the name of your fighter DAVID TUA.
To make all of the boxers a whole lot dumber, start the game with a fighter named JESSICA MELTON.
To make all the boxers fart, name your fighter ADAM GARDNER.
To enable Fat Mode, enter your fighter's name as RICH OBERDICK.
To become invincible, name your fighter MUHAMMAD ALI.
Unlock All Arenas
To unlock all arenas, enter LENNOX LEWIS as your fighter's name.
Unlock All Boxers
To unlock all boxers, enter MIKE TYSON as your fighter's name.