Mike Tyson's Punch-Out!!
aka: Punch-Out!!

Extra bout:
Enter 135 792 4680 as a password, then press A + B + Select to access "Another World Circuit".

Busy signal:
Enter 800 422 2602 as a password to hear a busy signal. Note: This was Nintendo's customer service phone number.

View credits:
Enter 106 113 0120 as a password, then press A + B + Select.

Regain energy:
Repeatedly tap Select after a round ends to regain energy. Note: This may only be done once per game.

Status Passwords:
WVBA minor championship - 005 737 5423
WVBA major championship - 777 807 3454
Piston Honda - 032 730 8442
Super Macho Man - 267 913 7638
Don Flamenco - 005 373 5423
Mike Tyson - 007 373 5963