Cheat mode
 
 At the "Press Start" screen, press X, B, L, R to unlock all boxers, 
 arenas, and game modes.  
 
 
 Big head mode
 
 At the "Press Start" screen, press X, B, Up, Down.
 
 
 Small head mode
 
 At the "Press Start" screen, press X, B, Down, Up.
 
 
 Flat mode
 
 At the "Press Start" screen, press Down, Up, B, X.
 
 
 All boxers
 
 Win the Bronze, Silver, and Gold belts to unlock all boxers including 
 Mike Tyson.
 
 
 
 Mike Tyson challenge
 
 Defeat Mike Tyson and win the Gold belt to unlock the undisputed 
 champ mode.
 
 
 
 Play as Iron Mike
 
 Win the Mike Tyson challenge to unlock Iron Mike, the early version 
 of Mike Tyson.