Ready 2 Rumble Boxing: Round 2

Michael Jackson:
Highlight the "Survival" option at the main menu, then press Left(2), Right(2), Left, Right, L + R. Alternately, successfully complete the game in arcade mode two times to unlock Michael Jackson.
Information in this section was contributed by chri90.

Shaquille O'Neal:
Highlight the "Survival" option at the main menu, then press Left(4), Right(2), Left(2), Right, L + R. Alternately, successfully complete the game in arcade mode five times to unlock Shaquille O'Neal.
Information in this section was contributed by chri90.

Zombie boxer:
Press Left, Up, Right, Down, R(2), L at the character selection screen.
Information in this section was contributed by chri90.

Thin boxer:
Press Right(2), Up, Down, Right, R, L at the character selection screen.
Information in this section was contributed by howididit.

Fat boxer:
Press Right(2), Up, Down, Right, R(2), L at the character selection screen.
Information in this section was contributed by howididit.

Big fists:
Press Left, Right, Up, Down, R, L at the character selection screen.
Information in this section was contributed by howididit.

Freak E. Deke:
Successfully complete the game in arcade mode to unlock Freak E. Deke.

G. C. Thunder:
Successfully complete the game in arcade mode three times to unlock G. C. Thunder.

Wild "Stubby" Corley:
Successfully complete the game in arcade mode four times to unlock Wild "Stubby" Corley.

Freedom Brock:
Successfully complete the game in arcade mode six times to unlock Freedom Brock.

Rocket Samchay:
Successfully complete the game in arcade mode seven times to unlock Rocket Samchay.

Robox Rese-4:
Successfully complete the game in arcade mode eight times to unlock Robox Rese-4.

Bill Clinton:
Successfully complete the game in arcade mode nine times to unlock Bill Clinton.

Hillary Clinton:
Successfully complete the game in arcade mode ten times to unlock Hillary Clinton.

Rumbleman:
Successfully complete the game in arcade mode with every character, including the hidden characters. Then complete the game in arcade mode one additional time, under the hard difficulty setting.

Champion costumes:
Win the game in championship mode to unlock the champion costumes.