Instructions
Listen to Doc. He's still training you, and he tells you how to block his next attack. "Uh...dodge!" means you should dodge to your left and send five jabs to his face. When he says "duck this one," hold the "Down" button to duck and then counter with five jabs. "Keep em up" means you should hold the "Up" button to block both of Doc's punches and then counter with four jabs.
Pull away from Doc when he takes out his candy bar. He eats it to regain his heath, and you can't stop this in training mode. In sparring mode, watch for the hand holding the chocolate bar. When he holds it out, give him a body blow to that side. If you successfully knock the chocolate from Doc's hand, he gets angry. He gives you a warning the first time. The next time, he rips off his shirt and aggressively attacks you.
Use short jab combos when Doc isn't speaking. When you miss, he retaliates with non-telegraphed punches, so watch out.
Dodge left when Doc says "I invented the Star Punch." When he misses, counter with a right jab and a short combo.
Lose three times and then win three complete games to see Doc's secret ending.