Babak Anvari’s “Wounds” is a movie that includes gaping injuries, rearranging heads, and thousands of cockroaches, but you come away with the distinct impression the filmmaker just wanted to make a film about a break-up. Perhaps that’s just projection; whatever the intention, this is a gimmick-based, jump-scare-riddled horror movie that‘s also a relationship psychodrama, but there may be too much of each element to satisfy the target audience for the other.

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Its opening scenes play best, coming into this story from an odd, oblique angle that puts the viewer off-balance for a good, long while. We meet Will (Armie Hammer) at work; he’s the bartender for a New Orleans dive, and he seems at home there, joking with the regulars and helping himself a sip or six. Writer/director Anvari (“Under the Shadow”) keenly captures the weird tension when one person has clearly had way too much to drink, much more than the rest of the room; that tension simmers for a while, then boils over into an ugly, grisly bar brawl. A table of college kids look on in horror, then flee; one of them leaves a cell phone behind. Will takes it home with him, and sends a heads-up text. Then he looks at the pictures. Big mistake.

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It soon becomes clear that by poking around on the device, Will and live-in girlfriend Carrie (Dakota Johnson) have opened up a world of trouble, manifested first in strange noises and creepy texts, soon giving way to unnerving hallucinations, strange bruises, and body horror. The gory, disturbing images get into their heads; they end up sweaty, paranoid, and delusional, confronted with strange phenomenon they should be able to explain away, but can’t. And then Carrie starts poking around online (never a good idea), discovering theories of using wounds to “transcend physical boundaries” and “connect with higher beings.” Oh-kay.

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But none of that stuff is really fleshed out; it’s more window dressing. The hook here is a kind of J-horror haunted cell phone situation — a pretty goofy premise, if we’re all being honest, yet taken with increasing seriousness as the picture soldiers on. But Anvari orchestrates the dread-filled atmosphere and shock jolts well (he really keys in on the way a phone on vibrate can give you a good startle), and the unraveling of these two seemingly ordinary people is compelling.

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And maybe that’s the problem; that material is so keenly observed and sharply played, the supernatural element becomes a distraction. When we first meet Will and Carrie, it’s already a relationship in trouble, burdened with trust issues (well-founded, we soon discover) and jealousy. Hammer and Johnson bounce off each other well, and their arcs come across; Hammer is quite convincing as the bearded-flannel-bartender dude, and he slowly, skillfully reveals the bitter prick just under the affable-bro exterior; Johnson makes an impression (she always does) in what is, comparatively, kind of a nothing role.

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Ultimately, it’s hard to figure out exactly what movie Anvari was trying to make. Those loosey-goosey early scenes exhibit a wry sense of humor and a wild, anything-goes storytelling sensibility; there’s also something thrilling about the way the horror elements are forgotten, for a hefty middle stretch, as Will embarks on an evening with a bar regular (the wonderful Zazie Beetz, from “Atlanta”) whom he’s clearly hot for. But then Anvari abandons all the truly compelling material in the final stretch and in favor of some fairly typical waking nightmare imagery, followed by a big gross-out climax, and then a cheapo cut to black. It’s kind of a bummer. These folks deserved better. [C+]

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