Beat the game at any level without loosing a round. After you beat Mr. Big, Geese will appear and challenge you.
Super blow technique
You can use the Super Technique of Blow. You do this: First, you must have a backup of "Art of Fighting" where this technique is saved. In "Art of Fighting 2" choose Data load , then "Art of Fighting". You'll start the game with the Super Technique of Blow.