LEGEND: G = Green button, Y = Yellow button, B = Blue button
To automaticlly win the round, pause the game and press 'GYGYGYBYBYBYG'. Now unpause the game and the fight will finish with you as the winner.
For infinite credits, press 'BYBYBYBYG' on the options screen.
To fight as PoPazz, on the options screen press 'GYBGYB'.
To fight as Shadow Fighter, on the options screen press 'BYGBYGBYGBYG'.