Secret Characters
Once you win the world title, defend your title until Jackel challenges you. Once you beat him save your victory. Go to Exhibition and load from you memory card, then go back to the computer fighters and where the four question marks were will be four secret characters; Beastman, Jackel, and two others who look similar to Bert and Grover

Contender Quick Recovery
When you get knocked down rotate the D-Pad and press other buttons repeatedly to get up faster.

Main Event Characters in Two-Player Mode
Start a new boxer in the Main Event. Pick one of the boxers and imediately save him to your memory card. Exit, then repeat with another character. When you have saved each boxer start a two-player match. At the character select screen press SQUARE to pick one of the other boxers from your memory card.

Play as "Jackel"
To play as Jackel you first have to go to the "Main Event" and save any player. Then go back into "Exhibition" and load the player you saved by pressing SQUARE. After you highlight the player press SQUARE again and you should have Jackel in your second "Mystery Box".

Extra Characters in Exhibition Mode
After you've won the World Championship title, go to the Exhibition Mode character selection screen and press SQUARE. After this press SQUARE again and you can be Jackel, Goober, Rascal, and Beastman.

Newspaper Photograph
During a match in main event mode, turn on the analog and press in one of the sticks(L3 or R3)and it will look like it's taking a photograph. When the fight is over and the newspaper screen comes up it will show the picture that you took.