Unlimited continues:
Hold Up and press A + B + C when the number of remaining credits is displayed at the continue screen. One additional continue will be added each time this controller action is completed.

Perpetual fight:
Choose the "Control" selection on the options screen. Highlight the "Point" option. Hold B and set this value to "0". Start a two-player versus battle mode game. The point globes will be replaced by counters that represent the number of rounds that were won. Reset the Genesis to end the game.

Fight as Geese Howard:
Select versus mode, then highlight the option for either a one or two player game. Hold Left on controllers one and two and press Start.