47 Meters Down was completed last year and readied for an August 2016 VOD release (under the title In the Deep), and its stay of execution came about for one reason and one reason only: because about five weeks before its street date, The Shallows came out and got shockingly good reviews and made a shockingly healthy amount of money, for what it was. In the faultless logic of film executives, somebody decided that this meant that shark movies were back on top of the world, and thus was 47 Meters Down purchased, given back its original title, and given almost exactly the same theatrical release frame as The Shallows, 51 weeks before.

Absolutely everything in the first paragraph should be taken as the first warning sign. The second warning sign: the distributor that bought the rights to 47 Meters Down is called "Entertainment Studios Motion Pictures", and its logo looks like it was made in MS Word in 1998.

The happy ending to all of this is that the gamble paid off: 47 Meters Down will never match The Shallows, but it was already in the black by the end of its opening weekend in the North American market. For the audience? Much, much less of a happy ending. By the standards of cheap shark thrillers, 47 Meters Down is perfectly serviceable, but it's certainly no more than that, and it takes a generous viewer to overlook the by-the-books storytelling.

Here's what we've got: Lisa (Mandy Moore) is the boring sister, and Kate (Claire Holt) is the fun sister. They're vacationing together in Mexico, when Lisa drops the bombshell: her boyfriend just ended their relationship, and she's taken the blame entirely on herself, and her damnable lack of wacky funtime shenanigans. Kate has the exact perfect solution. Step 1: make out with a pair of cute locals, Louis (Yani Gellman) and Benjamin (Santiago Segura). Step 2: join the same cute locals for a trip out on a shark-watching boat captained by an American named Taylor (Matthew Modine, whose presence as our "acting veteran" for the evening speaks to the budgetary level this is operating at), and take plenty of selfies in the shark-proof cage where they'll be surrounded by great whites. The sisters' short time in the cage, 5 meters below the water's surface* goes by swiftly and restores Lisa's sense of vitality, and she pledges herself to living life the fullest from here on out.

Or, y'know, there's a rather convenient accident that sends the cage hurtling to the bottom of the ocean, 47 meters below the surface, and the sisters have to scramble for a solution that involves neither death by drowning nor death by shark attack. Of course, the killer animal movie has its own noble and time-honored formula, but something about this particular case feels excessively draggy; Lisa and Kate have such splendidly narrow, one-note personalities, that any time we spend with them out of the water feels like time wasted. And it certainly doesn't help matters any that the film's very title hangs like the laziest sort of dramatic irony over the entire first act.

Of course, nobody comes into a movie like this for any reason other than the obvious: what happens once the cable breaks, and the shark cage plummets into the watery gloom, with only a few feet of visibility (at a depth 47 meters, there would be substantially more light than we see in the film). Credit where credit is due: this part of the movie works. It's hard to imagine how it couldn't: just the mere power of suggestion demands that as you sit in a dark theater, thinking about the notion of being trapped in the black water, there has to be some kind of visceral, physical reaction (this is certainly the best benefit to the film of graduating from VOD to a theatrical release; I can't imagine it having much of an impact at all in a living room or, God forbid, on a laptop). It's a shark movie that, frankly, would do just as well to lose the sharks; what the film is best at is communicating a dreadful, claustrophobic sense of pressure and containment. Director/co-writer Johannes Roberts and cinematographer Mark Silk make outstanding use out of the limited space of the shark cage, and the restriction that the scuba masks put on the close-ups of the main characters. Between the dark, and the feeling of overwhelming confinement, 47 Meters Down would have nearly as much of a queasy-making effect if it was just that, and the sense of powerlessness that comes with.

Aye, but it does have sharks, and not bad ones; there's little enough that has to be done via CGI that the effects work holds up perfectly well. They feel a little bit more like the plotting psychopaths in a slasher movie than animals of any sort: invariably waiting for those moments when the plot demands that Lisa or Kate journeys out of the cage to make radio contact with the boat or what have you, invariably waiting for the exact moment when the audience will jump highest. At one point, the sharks obligingly wait for Kate to set off a waterproof flare so that we can see - ye gods! - that they're right there! And it's almost exactly as dumb as it is surprising, though at least there turns out to be a story reason why the sharks aren't acting like sharks in that precise moment.

The upshot to all this is, if the thing you require in life at this moment is an hour and a half of feeling lightly tense in a movie theater, 47 Meters Down can provide that, and that is very nearly the only thing it can provide. It makes good use of its concept, and that's just about it: Roberts and co-writer Ernest Riera can't even get up that modest running time without labor, and outright cheating, and neither Moore nor Holt does much to make their characters interesting (given the amount of time they're strapped into scuba gear, there's really not all that much they could do). The "trapped in a horrible place" thriller subgenre has produced worse than this, and better than this, and fans of killer shark movies have learned to be forgiving; but 47 Meters Down certainly doesn't try to extend its appeal behind that forgiving audience, not even a tiny bit.

*The one easy way to tell this American B-picture was actually produced in the UK: it never once translates its measurements into feet.