The worst thing we can say about Oxygen is that it is a very gimmicky thriller based on an overfamiliar gimmick, but done by a director with a skill set extremely well-positioned to make the most of that gimmick, and starring an actor who wrings everything she possibly out of basically only three elements (her facial expressions, her tone of voice, her breathing rate) to deepen the gimmick with complex emotions. Actually, the worst we can say about Oxygen is that it's a Netflix original sci-fi film, a combination of genre and distributor that has one of the ugliest success rates in contemporary cinema, but since this is quite possibly the best Netflix sci-fi film ever made, that's not fair to hold against the movie.

Oxygen is, as it turns out, much better than the worst we can say about it, but that's not clear for the first hour of the 100-minute film, so let's take what we're given at the start. The gimmick is that, other than flashbacks (and these are actually somewhat numerous and critical to the development of the narrative), this is all set in one very small location - a futuristic cryogenic chamber that roomily accommodates a single human body, but it's still essentially a science coffin, making this basically just a genre overlay of the 2010 thriller Buried. The director is Alexandre Aja, who has never been further from his roots as one of the most notorious splatterpunk filmmakers of the early 2000s (though he gets some good mileage out of queasy shots of intravenous needles going in and out of human limbs). But he has other talents, and the ones on display here are akin to the ones he showed off to such effect in his last film, the 2019 alligator thriller Crawl: ruthless storytelling efficiency and tremendous visual flair in extracting every possible interesting angle from a limited environment, while steadily escalating tension. And the actor is Mélanie Laurent, the terribly interesting French movie star who is typically better than the movies she's saddled with, and maybe that's even true here as well. But since most of the movie is Laurent, the top half of her body providing very nearly its only visual subject worth talking about, the quality of her performance and the quality of the film are inextricably linked.

After a suitably abstract opening scene involving a rat running in a seemingly infinite maze, the film opens in a state of quasi-body horror that it's going to play with, on and off, for most of its running time: a figure wrapped in a kind of flexible artificial skin jolting awake, right under the oppressive weight of the camera, in a hideous approximation of expressionless screaming; it tears off the skin to reveal Laurent, gasping for - wait for it! - oxygen. It's almost tempting to say nothing else about the story, since one of the great pleasures of Christie LeBlanc's script is that we spend the entire movie with precisely the same knowledge of her character, who presumably as a side effect of the cryogenic freezing process can't remember so much as her name or what events led her to end up in this dimly blue-lit little tube, with all kinds of needles running into her, and nothing to help but a voice-activated digital personal assistant named M.I.L.O. (voiced by Mathieu Amalric, who is perfect at providing a flat, monotonous  that also feels distinctly threatening and arrogant, even in its robotic inhumanity). This proves to be almost as frustrating as no help at all, but by carefully thinking through her inquiries, the woman is able to start piecing together information about her situation, namely that her pod is leaking oxygen for some reason, and if she is very calm and breathes with great tranquility, she'll probably survive for about 72 minutes. Since she is very much not calm, that will probably be more like 43. And so the rest of the movie is basically nothing but trying to figure out the right search terms to laboriously use the pod's external communication systems to figure out who she is, where she is, and who in the outside world can help her do something about it.

I concede that nothing about that sounds gripping, but Oxygen has a few things going for it. The most important of these, obviously, is Laurent, who is controlling every single element of her minimalist performance impeccably - and this is good a place as any to mention that, being a Netflix original and all, one's attempt to watch the film will most likely involve it auto-playing in one's local language, thanks to the streaming company's inexhaustible reservoir of dubbing services. This is to be greatly avoided: seeing Laurent and Aja work in their native French (his first time since his 2003 breakthrough, High Tension) is absolutely the right way to go, especially since so much of her performance lives entirely in her tone of voice. But as I was saying, Laurent is up to miraculous things, in what's easily the most technically impressive performance I've ever seen her give, and maybe the most emotionally layered, as well, because of the purity of the arc she has to build across the film's 100 minutes: from a pure blank slate to a human of a fully-explored history and backstory that has left her wise and sad; from pure animalistic survival instinct to the purely intellectual register of someone who has fully comprehended what it would mean to die (this isn't, believe it or not, any kind of spoiler).

Without Laurent, there would be no movie, but framing her performance is one hell of a great piece of cinematic craftsmanship, carefully worked out by Aja, cinematographer Maxime Alexandre, editor Stéphane Roche, and production designer Jean Rabasse so that every camera position tells us something about the woman, the space, or the escalating stakes of her remaining trapped there. Or sometimes not. Sometimes, it's just about the sheer visual pleasure of giving us some wild new angle that respects the cramped quarters of the tube but also creates a striking composition in its own right. Or in one case, brassily shows off that Aja and Alexandre figured out how to squeeze a 360-degree spin into this teeny-weeny space, and were content to use it in a location where it wasn't going to be ruinous to have that kind of super-visible gesture, though arguably it would have been no worse off with something a bit more sedate. Still, you put a movie in a coffin, the instinct to figure out how to place the camera in every part of that coffin and point it in every direction must be pretty strong (Buried did much the same thing, in a more generally minimalist film), and they do it well.

But even more than showing off, what the craft is doing in Oxygen is providing it with its sense of urgency - the ticking clock feels unusually present here, even if it's pretty clear that they're cheating sometimes (the film is not, after all, between 43 and 72 minutes in length) - but also a kind of transcendent, floating quality. It's a sleek, glossy future that we see in its tiniest possible incarnation here (when the woman has flashes of memory, they generally take the form of standard issue "lazing about in sunlit glens" moments that have absolutely nothing to do with science fiction), with M.I.L.O. taking the form of an amorphous floating circle of deal filmanets, gently bathing the woman's face in soft unnatural light; it's soothing in a clinical, austere way, which also fits, given that M.I.L.O. spends much of the running time trying to prepare her for death.

All very good stuff, for the first hour, and then there's a shift. But also there isn't, sort of. It's still the same movie operating the same way, but it somehow becomes indescribably expansive. Again, it's a pivot from the raw terror of claustrophobia to a spiritually reflective musing on who we are  and what it means to be a fleshy object that can be broken in a million ways and will die even if none of those ways occur. Somehow, it is perfectly natural that this should be the case - and with Aja directing, the film doesn't even have to sacrifice having the goods as a grubby little thriller to get us there. Oh! how I wish I could talk to you more about those last 40 minutes of the film, which are constantly shocking and surprising but also have the solemn inevitability of fate. It is a French movie, after all, even if it spend some of its time in development as an English-language production. Existential morbidity was the film's birthright, and it makes the very best of this. But even if the film goes to good to great on account of those late developments, it was never in need of salvaging: at its very weakest, Oxygen amply gets the job done as a thriller, and it is very rarely at its weakest.