Do double damage:
Enter DOUBLEDAMAGE as a name for a created boxer in career mode.

Invincible boxer:
Enter INVINCIBLE as a name for a created boxer in career mode.

Sepia tone graphics:
Enter SEPIA as a name for a created boxer in career mode.

Black and white graphics:
Enter BAW as a name for a created boxer in career mode.

Full attributes in career mode:
Enter 100% as a name for a created boxer in career mode.

Baby on screen:
Enter NALU as a name for a created boxer in career mode.

Fight as Ashy Knucks:
Enter KNUCKS as a name for a created boxer in career mode.

Fight as Barry Sanders:
Enter SANDERS as a name for a created boxer in career mode.

Fight as Jason Giambi:
Enter GIAMBI as a name for a created boxer in career mode.

Fight as Junior Seau:
Enter SEAU as a name for a created boxer in career mode.

Fight as Owen Nolan:
Enter NOLAN as a name for a created boxer in career mode.

Fight as Steve Francis:
Enter FRANCIS as a name for a created boxer in career mode.

Fight as The Bulldog:
Enter BULLDOG as a name for a created boxer in career mode.

Fight as a baby:
Enter BABY as a name for a created boxer in career mode.

Fight as a cyclops:
Enter EYE as a name for a created boxer in career mode.

Fight as a clown:
Enter CLOWN as a name for a created boxer in career mode.

Fight as a gorilla:
Enter GORE as a name for a created boxer in career mode.

Fight as Schmacko Throb:
Enter THROB as a name for a created boxer in career mode.

Signature moves:
Press Triangle + Circle to do a boxer's signature moves. For example, press Triangle + Circle as David Tua and he will do his devastating left hook.

Illegal kick:
Press Triangle + Circle + X + Square during a match to illegally kick your opponent in the midsection.

Illegal head butt:
Press R1 + R2 and press Triangle during a match.

Illegal low punch:
Press R1 + R2 and press X during a match.

Illegal kidney punch:
Press R1 + R2 and press Circle during a match.

Illegal elbow:
Press R1 + R2 and press Square during a match.

Bite opponents ear:
Press L1 + R1 to clinch your opponent. Then, press Square + X + Triangle + Circle.

Hint: Fight yourself or advance fights in career mode:
After pressing X to select your next opponent, quickly press Up or Down to switch opponents. Pressing Down will result in you fighting yourself.