Appropriately for a surreal realm comprised of inexplicable angles that stretch across impossible dimensions and seem, as one explorer puts it, cobbled together by “construction workers on acid,” the Backrooms, as a premise, have no precise parameters. You might think of it less as a story than a shared alternate reality, originating as a creepypasta (internet-based urban legend) and then taking on a life of its own as fans added bits of lore and started to spin it into works of their own.

Now that concept seems poised to break containment into the mainstream with Backrooms, a slickly produced feature boasting a buzzy studio (A24), bona fide arthouse stars (Chiwetel Ejiofor, Renate Reinsve) and established genre leaders (James Wan, Osgood Perkins) among the producers.

But if the film captures something of the concept’s intriguing unease — with 20-year-old director Kane Parsons drawing from his own Backrooms-set short films, created when he was just a teenager — its underbaked storytelling made me wonder if some spooky ideas might be better left as whispers in the dark.

Though the Backrooms are ineffably strange (“Imagine describing a dog to someone who’s never seen one and then asking them to draw it,” characters reply when asked to explain them), the world we cut through to get there is almost suspiciously normal. In a quiet California suburb circa 1990, Clark (Ejiofor) is a failed architect who makes his living as the proprietor of Cap’n Clark’s Ottoman Empire — or rather tries to, since the discount furniture store’s total lack of customers suggests a business on the verge of collapse. His life has gotten miserable enough that he’s seeing a therapist, Mary (Reinsve), to deal with the implosion of his marriage.

Up late watching TV at the store one night (because he’s been sleeping there ever since his wife kicked him out after a bitter, booze-fueled fight), he ventures downstairs to fiddle with the breaker, whereupon he discovers he can just kind of slip through one of the walls, as easily as stepping into a beam of light. On the other side lies a room not unlike the windowless carpeted basement he’s emerged from. But this one is lit in a sickly institutional yellow, with all its furniture haphazardly piled in the middle. Also, it seems to go on forever. No matter how deep Clark wanders into it, all he finds are more rooms, corridors, staircases, doorways, crawlspaces.

It’s a deliciously creepy concept, tickling the same elemental unease provoked by other liminal horror stories like 2022’s unsettling Skinamarink or Mark Z. Danielewski’s 2000 novel House of Leaves: If structures like homes and offices and stores are meant to contain and protect, there’s something disturbing about one that refuses to conform to those boundaries — that shifts beyond the known laws of the universe so that what should have been a safe space becomes a trap.

The horrors that lie within this particular trap take some time to reveal themselves. At first, our disquiet and Clark’s mostly stem from sights that, while not overtly threatening, simply feel wrong: a stop sign printed backwards and erected in a dark room, a cardboard cutout fitted with a tape recording of messages in foreign languages, shoes embedded in the floor at an angle that suggests said floor materialized suddenly out of nowhere to slice right through them.

But eeriness for its own sake has its limits. The longer we spend exploring the Backrooms, the less frightening and more random these oddities start to feel. They seem designed not according to some internal logic of this universe or psychology of these characters but simply as an attempt to keep us guessing; it works only until it becomes apparent that there are no meaningful answers forthcoming.

Meanwhile, Clark and Mary (to say nothing of other minor characters played by Mark Duplass, Finn Bennett and Lukita Maxwell) are painted in extremely broad strokes. Even allowing that one of the movie’s central concerns is the way we create mental loops that keep us fixed in our miseries, the choice to define each of them through a single formative trauma and nothing else renders them too flat to care about.

I suppose the advantage of Clark’s lack of any other traits, including a self-preservation instinct, is that it makes him an ideal conduit for us into this universe: Since he never stops to consider whether wandering freely around what amounts to a haunted maze might be a bad idea, we never have to stop poking around it either. The further he goes, the more harrowing things get. The roar of a monster that had seemed distant at first seems to grow louder and more frequent, evidence of its violence clearer and harder to ignore (though never very graphic; Backrooms traffics more in dread than gore).

In its best moments, Backrooms brushes up against something bittersweet about the way our memories warp a little every time we access them, until they’ve been stripped of real details and we’re left only with the emotional imprint they’ve left behind. In one striking sequence, the camera glides down a succession of living room floors, each one growing more abstracted until all that remains is a pitch-black hole radiating menace from a corner. In another, grotesque humanoid figures are frozen in a dinner table scene, so lacking in feeling or agency that they do not protest even when they’re stabbed.

At its worst, Backrooms tries to raise the stakes by trading subliminal chills for more explicit but also more generic thrills, culminating in an action-y climax that seems to exist solely to fulfill audience expectations of how a mainstream horror movie is supposed to end. The film wants to invite you in, but the more the Backrooms try to explain themselves, the more quotidian they feel. This is a realm better left to the shadows, where unsuspecting souls can fall down its rabbit holes before they even know what’s hit them.