This Game Is So Hard!

This thread is inspired by me listening to old video game music while lurking online. I began listening to the basic theme for one game and it reminded me how hard it was to actually complete this game. The game that I'm speaking of is Mike Tyson's Punch Out!

Mike Tyson Punch Out was one of hardest games that I've ever played in my life. I spent so many hours trying to beat Mike Tyson and failing over and over again. Of all of the games for the Nintendo, I don't think that I can think of any character on any game that I had a harder time with. I remember thinking that because this game wasn't an action or adventure game, that this game would be a lot easier to finish than many others. I was gravely wrong though, and I haven't beaten Mike Tyson but probably one time that I can remember.

Does anyone else have an NES game that was extremely difficult to finish or that shocked them and was harder than expected?