Unlock Characters
Fred - Beat arcade mode with any character
Halo - Beat arcade mode with Fred
Chester - Win 15 matches in survival
Abe Lincoln - Beat arcade mode with all characters
Unlock Movies
Successfully complete the game in arcade mode with various characters to unlock movies.
Break bones
Get your opponent's life to a certain point (red zone). Then, press [Down]+[A]+[X] or [Up]+[X]+[Y]. This is useful when your goal is to break that person's arm.
Easy wins
As soon as your opponent gets back on his feet, execute a punch combo. You only have a small amount of time to hit him when he is not blocking you. Kicks do not work as well, as they usually duck faster and can sweep you on the ground. A good combo would be [X], [Y], [X], [Y].
Opponent fighting styles
A martial artist is a fast punch and kicker. Brawlers do heavy damage with grapples, but are very slow at punching/kicking. The other types are a mix of these two and have respective differences, such as heavy punch/kicks but slow punch/kicks, etc.
Unlock Movies
Complete arcade mode.
Unlock Skeleton
Start a new game in story mode and enter "Skeleton" as your name.