Super Metroid IMO didn't feel nearly as dark and dreadful as Metroid II, be it the lack of colors, the dark corridors, no map, Metroids lying in wait to hatch and attack, very little music in game, all kinds of factors. In that one you truly are alone, but at that time, you didn't know what lied in wait for you at the end of the game. And when you did, it had a bittersweet ending that fed directly into the story of Super Metroid. Super Metroid was epic though, at that time we had seen nothing quite like it. Sure it played like the original game, but this time the games backgrounds were filled with life and beauty.
Zero Mission expanded on the original games story, and unlike the first game, you didn't have to use a password, and you had a map. Great game, it along with Fusion, SM, Metroid II, and the original, I am glad to own in my collection.
As for classic gaming, other than a brief week with GTA V, classics are all I play. From NES, to golden age arcade, to PS2 arcade compilations, to the 32 bit PS1 and Saturn, to Wii VC and PSN PS1 classics and Capcom arcade compilations, tons of games owned, but always a difficult decision what to play.