Mike Tyson Heavyweight Boxing Master code: Press Square, Circle, L2, R2 when "Press Start" appears at the title screen. All created boxer items: Press L1, R1, X(2), Triangle, X when "Press Start" appears at the title screen. Big heads: Press Square, Circle, Up, Down when "Press Start" appears at the title screen. Small heads: Press Square, Circle, Down, Up when "Press Start" appears at the title screen. Random sized boxers: Press Square, Left, Up, Triangle when "Press Start" appears at the title screen. Flat mode: Press Down, Up, Circle, Square when "Press Start" appears at the title screen. View full credits: Press X, Triangle, Square, Circle when "Press Start" appears at the title screen. All boxers: Win the Bronze, Silver, and Gold belts. Mike Tyson Challenge: Defeat Mike Tyson and win the Gold belt to unlock the undisputed champ mode.. Fight as Mike Tyson: Win the Gold Belt to unlock Mike Tyson in single player mode. Fight as Iron Mike: Win the Mike Tyson Challenge to unlock Iron Mike, the early version of Mike Tyson.