All venues - At the game mode selection screen, hold or repeatedly tap Left until the sound of a bell is heard to unlock all venues.
Avoiding knockouts - In order to avoid a knockout, when your opponent gets close to you perform a grab. You will then exit knockout mode.
Better ring performance - Make your ring entrances very extravagant; the more extravagant they are, the more the crowd will like you and the better you will perform.
Box as Ghetto Fabulous - Enter "GETFAB" as the first name of a created boxer. Save the created boxer and Ghetto Fabulous will be unlocked under the heavyweights roster.
Box as Little Mac - Enter "Macman" as the first name of a created boxer. Save the created boxer and Little Mac from the Punch Out!!! games will be unlocked. Alternately, successfully complete the Super Punch Out! mini-game. Note: This feature is available in the North American NTSC version of the game.
Easier wins - Become skilled with the jab and straight combo. The CPU will parry it after a few times. Then, throw your hook or uppercut.
Extra fight store items - Although you can turn pro at any time, winning an Amateur title belt will unlock equipment you cannot find elsewhere.
Small fighters - At the venue selection screen, hold Up until the sound of a bell is heard. Select a venue to begin a fight with small versions of both fighters.