Perfect Fight Glitch
Well, I was trying to beat the boss on easy without continuing. I beat the first two stages with ease (Not really I was at 0 lives). Then came the final bout in the sky and he ran all the way to the left and just stood there. I thought he was going to shoot but he just stood ther aimlessly. The helicopters arrived, but he made no attempt to blow them up. I killed him and he fell off as usual and I got the "Perfect Fight" achievement.
I was just curious if this had happened to anyone else.