My husband played Super Metroid for the first time last night. I don't know how you get to be an adult gamer without it, but there you go. I haven't played Deus Ex yet, so I suppose we are "even"?
The main impression I got from him is he liked the atmosphere and the way the game foreshadows, but thought that Spore Spawn was boring. I assured him that most people think Spore Spawn is boring, I just couldn't remember offhand the trick for skipping it.
I do love Super Metroid though. It may be hard to explain to someone seeing it for the first time why it is very great. I could write an essay about why it's very great but I'm pretty sure that has been done many times. Here is one good example.
Maybe just watching it from the perception of someone who's never played it is more interesting, though it's clear old games don't have quite the same magic to someone who has no nostalgia for them. An interesting effect in and of itself. I can explain why systematically it's one of the best 2d games made, but he doesn't share the same enthusiasm for it that he does for other great 2d games for which he does have nostalgia, like Mario 3 or Megaman 2.
By the way, in case you were wondering, my user icon is in fact a modified Samus.