Bonus Venues:
Win a career mode fight at the Staples Center or Madison Square Garden to unlock it.
Fight as Ko Rey Mo:
Beat Ko Rey Mo in the light heavyweight division to unlock him.
The Burger King as your trainer:
Beat the Burger King event in career mode, then when selecting your trainer, press Down until Burger King is selected.
Fighting Styles:
Win matches in ESPN classic fights mode or career mode to unlock the fighting styles used by your opponents
Easy career wins:
Set Illegal Blows to 'off'. Get the illegal blow 'Elbow Shot' from the store, start a fight and use it as a counter. Ouch!