Thirty credits:
Hold L + R + Select on controller two and reset the game. Release the
buttons at the title screen. The credits may now be set to a maximum
of thirty from the options screen. 

Ten credits:
Hold X + A + L on controller two and reset the game. Release the
buttons at the title screen. The game will default to ten credits
instead of three. 

One round match:
Hold A + B on controller two and reset the game. Release the buttons
at the title screen. Each match will consist of one round instead of
three. 

Five round match:
Hold X + Y on controller two and reset the game. Release the buttons
at the title screen. Vs. mode matches will now consist of five rounds
instead of three. 

Super hard difficulty level:
Hold A + B + L + R on controller two and reset the game. Release the
buttons at the title screen. The difficulty level may now be set to
"Super" from the options screen. 

Play as Bosses:
Enter 9207 as a password. 

Vs. mode passwords:
Enter one of the following passwords to access different fighters: 

0197
1180
5093
4949
9207