I think the thing I liked the most was the tone. It was apocalyptic, yes...but very well done. It practically begins with an explosion and the death of 20-ish people, not to mention the death of "Baby Diego" and so you are instantly transported to this place were death is the norm and you understand the fear, sorrow, ambivalence, and hopelessness that the various characters are experiencing. Essentially, you begin to feel ambivalent, which is Clive Owen's initial emotion and you can relate completely. It becomes clear that the entire population has been desensitized to death (with the exception of Diego) and have even been prepared for it ("Quietus"--which is also a spell in Harry Potter).
It's very cool, however, that Julianne Moore is able to bring him back to the world of the living, and you can see why he would agree to her request. What else does he have to lose? Further, her death takes him out of "along for the ride" status, and into full-on activist mode. Finally, a death that mattered to him, after so many years of being one of the waking dead.
Another thing I found interesting was the Quietus poison. Despite the fact that everyone is going to die, with no hope for a future (even with Kee's baby...it's going to be difficult an imbred Garden of Eden), there is clearly a difference between ending life early (cop-out) and living it to the fullest. The point is really nailed home because both Jasper (Michael Caine) and Theo (Clive Owen) give their lives for the cause, and are able to accomplish something first. Even if we're just living to die, there's still something to live for.
On the surface, it's a fairly simple film. It almost provides the framework of this crazy, yet fathomable, not-so-future world and adds in a drop of plot for good measure. It's almost begging you to take that world and expand it. I overheard someone say on the way out that they wished there had been more, and while initially I did think that it wasn't entirely developed, that may have been part of the idea. What happens next is for you to contemplate and whether that world is realistic is up to you to decide. I think Cuaron purposely takes the seed, plants it, and gives you the smallest of sprout. To make it bloom and grow, you have to feed it. You have to ingest the ideas, think about the possibilities, discuss the story, and argue the semantics. The movie is only half over when you walk out the door. It must live on in your head, and I think that is where it truly succeeds.
Overall, it was almost uplifting, despite the evidence to the contrary. Anyone else feel that?
Also, phenomenal use of Picasso's "Guernica."
As a last, minor note: why the hell does Sean Bean keep doing horror films?! I'm not going to go see them. I'll just watch LotR: FotR over and over. Dammit, he's so hot!