@m308gunner Agree with you on Punch Out. I finally beat that a couple years ago. I couldn't make it past Sandman as a kid, and the first time I got to Tyson as an adult he scared the crap out of me. I put the game down for years. Once I got used to Tyson, he really wasn't that bad.
Other NES heavyweights for me were Battletoads and TMNT, neither of which I got very far in (I think I at least made it past the water level in TMNT).