Go to Gamewinners.com. thre you will find good cheats and strtegys

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 pass word 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 only works one time per round

Lose half your energy
hold select+ down before the first match to lose half your energy this code only works on matches after you beat bald bull for his title or after using the 777 807 3454 password, and only before the first match. You cannot use the Regain energy trick in round two or three if you first use this code. although this code is not very helpful, but it may be fun for someone who needs training or just for a challenge.

WVBA:minor championship 005 737 5423
WVBA: major championship 777 807 3454
Word Circuit: 267 853 7538
0-0 record at end: 932 820 8538
97-0 record at end:961 263 7938
pistin honda:032 730 8442
super macho man:267 913 7638
don flamenco:005 373 5423
Mike tyson:007 373 5963

This is all I know man hope it helps all these codes work.