To win every match (Against the computer players), pick Bahn as your character. When the game starts just press the D-pad in the direction of your opponent and hold it and press B to do a super punch. Repeat this procedure to win the match, and sometimes unharmed!
Finish the game on the hardest setting with any character, and they will be selectable on the Character Select Screen by scrolling past the visible list of characters.
Highlight a character and press up or down.
Pause the game and press X, Y and Z.