I don't want to suggest that the entire list is complete garbage just because it's missing a few movies, but the lack of A.I. on the list suggests that the people who made the list have completely different tastes than I do.
Eternal Sunshine is my favorite movie of the past 20 years, but I can see why that wouldn't be included. It's a fantasy-based romantic comedy, and the science aspects of the movie could have been replaced with magic and it wouldn't really have changed anything. If Joel and Clementine had their memories erased by a witch doctor instead of a computer, it wouldn't have made too much of a difference.
I'd put Eternal Sunshine in the same category as something like Being John Malkovich. You could classify it as sci-fi, but it's something else entirely. See also: every body switch movie ever.
Children of men bored me. I was like please be over soon. good ending but overall I just did not connect with it I guess.
I'd arge that Gravity should be far lower and District 9 and moon should be placed far higher, but in general it's a pretty good list.
Edit: Oh and if we are going to include Cloverfield I'd argue that Pacific Rim is far better. The first 30 minutes of cloverfield are terrible.