I still haven't beaten NES Metroid. I've gotten as far as the Mother Brain battle and the combination of the guns, the rings, and the lava kill me every time. I've only been partway through Metroid 2 as well. I haven't ever beaten SMB 1 & 3 either.
I have, however, beaten Super Metroid, Super Mario World and Mario 64. It's funny how extra features and better controllers can help a game.
And yes, I'm still stuck with the original, boxy NES controllers.