Sonic!
The only Sonic game I had for the Sega Genises was Sonic 2, which fortunately turns out to be the best one from what I've heard. Heh, I still have my Genises and all my games somewhere.
Other than that and Mrs. Pacman, all I had were Disney games. Most of those were too difficult for the age that I was when I got them. I was never able to get past third-ish level of the Lion King.
My uncle was nice enough to beat them for me; I enjoyed watching just as much as playing.
(I just woke up.
Sorry for the rambles.)