The stink of having been shot almost three years before it finally saw the light of a commercial release hangs over Underwater like a fart in church. It's not exactly the film's fault - part of the delay is because the 20th Century Fox release got tangled up in that company's acquisition by the Walt Disney Company - but it's not very hard, with the film in hand, to see why nobody felt the burning need to get it in front of a paying audience as soon as possible. Barring some nice-looking-for-the-budget CGI, and a couple of music cues, the film feels instantly dated, more like a '90s creature feature than anything from any genre that was a proven moneymaker in the 2010s. And even in the '90s, it would have been behind the curve; the film is a dead ringer for the curiously populous cycle of "what if Alien, but at the bottom of the ocean" thrillers that came out in 1989 and '90 - your Leviathans, your DeepStar Sixes, your The Rifts. And even those films were borrowing every beat of their plots from a movie that was already 12 years old at that point. So Underwater is a throwback to a throwback (to a throwback?); if you are the kind of person for whom even the slightest trace of originality is a necessary prerequisite for finding a film worthwhile, swim right on by this one.

On the other hand, if you are the kind of person who would enjoy Underwater in the first place, you are most likely not that worked up about originality. Creature features are basically all the same film, after all, and have been since at least the 1950s; the hope with such a picture is never to be surprised, but to enjoy the specifics of the execution, and the design of the creature itself. And on this front, at least, Underwater works damn well. Director William Eubank and screenwriters Brian Duffield and Adam Cozad have apparently made their chief priority the delivery of genre setpieces at a steady clip; at 95 highly compact minutes, Underwater is at least the most efficient movie I have seen in a long time. And that's not even meant to be half-assed praise. There's something truly breathtaking about how quickly the film races through its opening act (it manages to pack a four-act structure into its slender running time), setting up its situation and main character with a leanness that recalls the best B-picture filmmaking of yore. As we learn from the opening credits,* a collage of topographic maps and newspaper clippings, we're headed to a state-of-the-art undersea mining rig, the Kepler, some 6.5 miles below the surface. Here, we meet mechanical engineer Norah Price (Kristen Stewart) as she prepares to brush her teeth early one morning. Though as she tells us in a moody, portentous voiceover, "morning" is a concept that has no meaning in the timeless, context-free hell of the deepest depths. Her hygienic regimen is interrupted by some shaking, more persistent than the rattles that are apparently part of everyday life on the Kepler, and in a flash she darts into the hallway, just in time to see the bulkheads start to breach, letting seawater in. She races to the nearest emergency hatch, where she bumps into Rodrigo (Mamoudou Athie); they're able to secure the hatch and safe the facility from immediate collapse. But the place still looks like hell, and for the next few minutes, they do their best Poseidon Adventure impression as they scramble across broken concrete chunks, through puddles, past sparking wires, and picking up nervous motormouth Paul (T.J. Miller, the most 2017 thing about the production) on their way to the remains of the control center.

This is all handled, please understand, within the film's first ten minutes. Underwater is ruthlessly efficient: it determines exactly what the minimum amount of information we need to follow the broad strokes of what's going to happen next, and that's all it gives us. Late in the movie, it starts to hand out a few bits and pieces of personalising details for the characters who are still alive at that point, presumably in an attempt to inject some pathos into the final act; but this is otherwise focused solely on the animal instinct of survival, locking us into Norah's POV both by stripping away any plot events she doesn't directly witness (with, I think, only one exception, midway through), and also by using lots of close-ups to keep us from seeing much of anything around or behind her. When she's panicky and confused, the camera shakes and the editing grows so choppy it's next to impossible to follow actions; at two different points, the blocking simply removes characters without explaining where they went.

This is, unquestionably, a frustrating and murky way to construct a movie - the middle is hard to follow in all its particulars - but it pretty much works at doing the one thing Underwater takes as its mission statement: to emphasise how unbelievably terrifying it would be if one were stuck 6.5 miles below sea level in a leaky metal box. That's it, that's the movie. It adds some wrinkles, in that sometime during the second act, the characters discover some sort of unfathomably hideous deep ocean worm the size of a human forearm that appears to be the larval stage of a large, vaguely humanoid and extremely toothy fish-being, but the point remains the same: we can't see very much, and we don't know very much, but we do know that what we can't see has a very high likelihood of killing the cast horribly, and without warning (the film's first death pushes right up to the edge of what one can reasonably get away with in a PG-13, and it's not even the monsters that do it).

There's something bracing about this, in addition to being frustrating; the film's strategy of throwing shit at us and letting us sort it out in retrospect isn't necessarily re-inventing the wheel, but it's nice not feel like a film is holding our hands the whole way for a change. The way it constructs characters is a bit more uncertain; these people barely even rise up to the level of clichés, and letting us see their personalities coalesce as the end result of their behavior in a high-stress survival situation would work better if there were actual personalities involved. It mostly falls to the cast to ground what we see in human psychology, and for the most part they can do this, if not with any real distinction, at least with workmanlike skill. Even the reliably awful Miller gets something interesting out of his character's fixation on a soothing totem, a plush bunny toy, and the characters who get more sustained screentime - Vincent Cassel as the Kepler's captain, Jessica Henwick as a researcher fairly new to the rig - find ways of implying genuine emotion in their boilerplate stories. As for Stewart, this is in some weird way one of the biggest tests of her movie star skills she's ever faced: she has to carry an entire film based on almost nothing but being able to exist in an interesting way, and while the film cheats by giving her a visually striking platinum-blonde crew cut, she keeps landing on different little notes that show her character's nerves, weariness, and level-headed pragmatism. The character is a transparent Ellen Ripley knock-off, and Stewart's no Sigourney Weaver, but she manages to keep the film lashed together around her.

The bigger concern than the human element, anyway, is how well the film smacks us with a crushing wet atmosphere, and it does so just fine. Underwater was shot by Bojan Bazelli; not an A-list cinematographer, but one with a fair number of impressive entries on his resume, including the notably stylish horror movies The Ring and A Cure for Wellness. My instinct has always been to credit director Gore Verbinski with those films' visual successes, but Underwater convinces me to re-evaluate that: Bazelli is doing a lot of work to amplify the shitty, insufficient lighting of the dying rig and the even more insufficient lighting of the characters' pressure suits once they have to start trekking across the sea floor, as well as the filmy murk of the sea bottom. It's a film with a lot of diffuse background lighting and hard edge lighting, all of it contributing to the overall feeling of not being able to tell what the hell is going on in a terribly unpleasant way.

On top of all of this, it has some great monsters. The larval fishbeast, which we see in the best lighting, is nothing; just a lazy clone of Alien's chestbursters. The bigger versions look goofy, but they also feel legitimately otherworldly, perversions of nature unknowable to science, with beady eyes that reflect the light in a terrific haunted house way. The biggest version is an utter treat, getting unusually close to evoking the sheer inconceivable wrongness of the elder gods that you find in the pulp writing of H.P. Lovecraft and his successors. It's enough to fully redeem the film from a third act that had mostly lost me, on account of how opaque the staging was starting to become; the film's climax is dumb and makes no sense, but it's got grandeur on its side, and a version of the "Smile you son of a bitch" moment from Jaws that's surprisingly enjoyable, given how ludicrously trite it is. Is the film good? No, obviously it's not. But a movie with a monster this marvelous doesn't need to be good to be fun schlock, and the monster's not even the only thing Underwater has going for it.

*For the record, the title treatment is a cheesy hoot: the production companies fade in and out, each one line lower on a black screen than the last, until the title itself appears, with wide enough kerning that it fills the width of the frame, all the way at the bottom. It's a prefect visual embodiment of plunging down into the depths, enough so that I am inclined to forgive how corny it is.