Mike Tyson's Punch out was definately challenging. If you could manage to play the first two rounds flawlessly, you could K.O. Mike in round two. If you let it go to the third round Mike would become very unpredictable in his patterns and punches, and would usually pummel you really good.
I can remember kids in my middle school spreading a rumor that if you used the Konami code a man mario would come out and shoot Tyson, and you would win by K.O. The rumor was valid for some time, as no one was able to even get to Tyson for a while to disprove this theory. I was glad to debunk the rumor myself, but still took some time before I could master Tyson and beat the game.
There was a hidden more challenging mode to play in this game, also, don't know how many people realize that or not.







