That's a tough question for me, because I wasn't great at a lot of games growing up. I'm not very good at platformers, but I used to be okay with SMB3 and SMW. The only game that comes to mind would be Ms. Pac-Man on Atari. I used to be great at that game, but I'm pretty lousy at Pac-Man games now.
Notable mention- I used to be able to get a 100 on the first airplane stage of Pilot Wings only using the throttle up and down, not the d-pad. It might not be much of an accomplishment compared to other gamers, but none of the other kids I knew could do it