At the character selection screen, press Left, Right, Left(2), Right, Up, Down, R(5), L to unlock all boxers, costumes, and more. If you entered the code correctly, you will hear a sound. Press X to cycle through the costumes.
At the character selection screen, press Left(2), Right, L, Left, Right(2), R(2), L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Left, Down, Right(2), Up, R, L, R(20), L. If you entered the code correctly, you will hear a sound. Alternatively, successfully complete championship mode to unlock the champion costumes.
At the character selection screen, press Left(2), Down, Right, Up, R(8), L, R(4), L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Left, Down, Up, Down, Up, R(20), L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Right, Up, Down(3), R, L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Right, Up, Down(3), R(2), L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Right, Up, Down(3), R(3), L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Right, Up, Down(3), R(4), L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Right, Up, Down(3), R(5), L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Right, Up, Down(3), R(6), L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Right, Up, Down(3), R(7), L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Right, Up, Down(3), R(8), L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Right, Up, Down(3), R, L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Right(2), Up, Down, Right, R(2), L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Right(2), Up, Down, Right, R, L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Left, Up, Right, Down, R(2), L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Right(2), Up, Down, Right, R(3). If you entered the code correctly, you will hear a sound.
At the character selection screen, press Left, Right, Up, Down, R, L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Right(2), Up, Down, Right, R(4), L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press Left(2), Down, Up, Down, Right(2), R(19), L. If you entered the code correctly, you will hear a sound.
At the character selection screen, press R(20), L, R, L, R(21), L, R(18), L, R(9), L, R(14), L, R(5), L, Left, Right, Up, Down, L. If you entered the code correctly, you will hear a sound. Pause the game to find 15 new camera angles.
At the character selection screen, press L, Down, Right, Up, Left, R(6), L, R(2), L. If you entered the code correctly, you will hear a sound.
At the main menu, press Right(3), Down, R, L. If you entered the code correctly, you will hear a sound.
Pause the game and press R, L, Down, Up(2), Left, R(3), L.
Pause the game and press R(2), L, Down, Up(2), Left, R(4), L.
Pause the game and press L, R(2), L, R, L, R(4), L, Left, Right, Up, Down.
Successfully complete arcade mode to unlock Freak E. Deke.
Successfully complete arcade mode two times to unlock Michael Jackson.
Successfully complete arcade mode three times to unlock G.C. Thunder.
Successfully complete arcade mode four times times to unlock Wild "Stubby" Corley.
Successfully complete arcade mode five times to unlock Shaquille O'Neal.
Successfully complete arcade mode six times to unlock Freedom Brock.
Successfully complete arcade mode seven times to unlock Rocket Samchay.
Successfully complete arcade mode eight times to unlock Robox Rese-4.
Successfully complete arcade mode nine times to unlock Mr. President.
Successfully complete arcade mode ten times to unlock The First Lady.
Successfully complete championship mode with all characters, then complete arcade mode on the hard difficulty setting to unlock Rumble Man. -From: ka0s@flash.net
At the character selection screen, highlight a boxer and press X.
Set the system date to January 1 to unlock a Baby New Year's costume for Joey T.
Set the system date to March 17 to unlock a leprechaun costume for the referee.
Set the system date to February 14 to unlock a lover's costume for Lulu Valentine.
Set the system date to April 23, 2001 to unlock a bunny costume for Mama Tua.
Set the system date to July 4 to unlock an Uncle Sam costume for G.C. Thunder.
Set the system date to October 31 to unlock a skeleton costume for J.R. Flurry.
Set the system date to December 25 to unlock an elf costume for Selene Strike and a snowman costume for Rumble Man.