Taunt your opponent:
Press A + B + C during the fight.

Skip introduction:
At the beginning the announcer will always say "In this corner player one" and "Let's get ready to rumble". If you want to skip most of that, hold A + B + C during the introduction. The announcer will just say "Player one" and will skip "Let's get ready to rumble."

Hint: Faster counting:
When you knock the fighter down, the announcer will count him out by saying "One, two, three, etc.". While he says "One" pause game play. The announcer will think he said the number completely, and then say "Two" quicker than usual. Keep repeating this with each number to get to "Ten" faster.

Glitch: Unsynchronized speech:
Make your opponent taunt you by moving away from him. Pause game play in the middle of the taunt. When you resume the game, your opponent will not be talking but his lips will still be moving.

Glitch: Disappearing boxer:
Try to knock your opponent down. When his head comes up and the crowd starts cheering, press Start. If done correctly, when he gets up you should disappear from the screen for about two seconds and then appear again.