Vadim Rizov’s review published on Letterboxd :
For a long time now, I've read contemptuous dismissals from adamant peers of pretty much any kind of CGI showboating on the grounds that "impossible" shots require little more than millions of dollars being thrown at a problem. It's true that slinging a camera from non-"space" into Sandra Bullock's helmet to assume her non-existent POV, then sending it back out into the equally unreal void etc. etc. lacks physical tactility or any easy sense of empirically quantifiable achievement — but it's also true that the shot had to be thought up in the first place, and Cuarón's concepts are pretty impressive. I don't think the movie's predicated on anyone into being hoodwinked into thinking "How real! What a feat! How did they do that!" With its baffling comparisons to Kubrick and Ophuls, Todd McCarthy's much-derided Variety review has served as a kind of synecdochal stand-in for all such ignorant responses or what the movie itself is trying to do, but that's again not terribly germane.
CGI is CGI; it's weightless and sometimes pathetically inadequate. (How are computer flames still so unconvincing?) But most of the first hour's shots are pretty exciting, detail-oriented spectacles: e.g. not just shooting the "camera" inside Bullock's helmet, but slowly adjusting the condensation-on-glass levels or the angle at which Bullock holds her head relative to light sources from the left, eventually resulting in an invisible diagonal producing a blue "flare" on the right. The overt artifice and impossibility of it all don't preclude being impressed; these are impossible shots, but they've been thought through on every level, and that's certainly something new to see. (Anyone who's ever grumbled about directors who seem to think digital's the same as film and who ignore its unique properties should be equally interested in what CGI is or could be rather than simply complaining that it's not The Real Thing imo.) Suspense can be generated in a literal vaccuum, partly because of the novelty of the setting: you don't know exactly where all the possible places to grasp onto on a space station are, so even if you can be reasonably sure Warner Bros. didn't spend ~$120 million to give us the dour spectacle of Sandra Bullock dying in space, you're not sure exactly where the last possible stopping place is.
I have a terrible feeling Cuarón believes his dialogue and stupidly heavy-handed plot/"themes" ("you have to learn to let go" not just said out loud but also visually illustrated come on) aren't just necessary evils to hoodwink a studio into funding his visual experiments but in fact Very Meaningful, but I can live with that. (There's a momentarily much more harrowing movie occuring, one about someone who suddenly realizes that there's a very high possibility they're going to die in a few hours, but Bullock's big monologue dilutes the realization.) There's a Ripley-in-panties moment early on, seemingly dispensed with so that the final shots won't be too objectifying, and I can live with that too. And yes, the score is unnecessary, diluting the bravura of removing the possibility of using sound for sudden shocks.
If you disdain corporate CGI spectacle on principle — that it's basically expensive frivolity, a distraction from Real Cinema — that's totally understandable, even laudable. I'm a weaker man than that and need a dose of expensive blockbuster fun every once in a while. I doubt I'll ever watch it again, but it's a diverting spectacle that got me to experience rare moments of real suspense a few times.
[Addendum: on Twitter, my bud Jason Overbeck noted: "Film writers: You should know, people who work in VFX laugh mockingly at you when you write 'CGI' instead of 'CG.'" Now I know. Now we all know.]