Night Terrors, Now with Paperwork
Sleep is the rare horror movie that understands two fundamental truths of adult life: 1) marriage is hard, and 2) you will never, ever sleep again once there’s a baby in the house. Jason Yu’s feature debut takes those anxieties, feeds them raw instant coffee, and traps them in a small apartment where the walls are thin and the nights are very, very long. The result is a razor-sharp black comedy horror that’s funny, tense, and uncomfortably relatable—like watching a parenting seminar hosted by a poltergeist.
The setup is simple: Soo-jin (Jung Yu-mi) and her actor husband Hyeon-soo (the late Lee Sun-kyun) are newlyweds about to become new parents when he suddenly starts sleepwalking. At first it’s just weird—muttering, strange postures, a bit of midnight zombie shuffling. Then he starts saying things like “Someone’s inside me,” and you realize this is less a sleep study and more a possession trial. Domestic Bliss, Meet Night Shift Horror
What Sleep nails is how claustrophobic the everyday can become when you’re terrified of the person you love. Most of the film takes place in one modest apartment, and Yu turns it into a pressure cooker. Crib in the corner, dishes in the sink, baby monitor humming—and somewhere in all that normality, something is very wrong. Critics have praised how the film slowly transforms domestic life into a nightly horror show without ever losing its grounding in reality.
There are no grand gothic mansions, no cursed villages, just a young couple trying to keep a newborn alive while dad might be possessed and mom might be losing her mind. It’s the kind of horror that feels like it could happen in the apartment upstairs, which is far scarier than any haunted castle.
A Two-Hander on the Edge of a Meltdown
Jung Yu-mi and Lee Sun-kyun are the film’s engine. As Soo-jin, Jung calibrates her performance with surgical precision: she starts as mildly anxious and steadily spirals into sleep-deprived paranoia without ever tipping into caricature. You can practically see the math in her eyes at 3 a.m.: “Do I call a doctor, a shaman, or a divorce lawyer?” It’s a performance that rightly earned her major awards attention at home.
Lee, in one of his final roles, walks a tightrope between goofy, sympathetic husband and unsettling, hollow-eyed stranger. By day he’s trying to nail commercials and reassure his wife; by night he’s a malfunctioning NPC who might strangle someone in his sleep. The chemistry between them sells the core horror: it’s not about demons or ghosts, it’s about what happens when trust in a relationship starts to fray one night at a time.
Laughing So You Don’t Cry (or Call an Exorcist)
For a movie about potentially supernatural violence in a tiny apartment, Sleep is surprisingly funny. Not gag-a-minute funny, but sharp, bleakly comic in the way real life is when everything’s going wrong and you haven’t slept since the Obama administration.
Jason Yu leans into absurdity: doctors give bland advice about “monitoring things” while Soo-jin is genuinely worried her husband might eat the baby. Her mother barges in with opinions and, eventually, a shaman, because when modern medicine shrugs, Korean horror tradition steps in with bells and incense. Critics have singled out the film’s “sly and absurd” tone and its delicate balance of humor and dread, and they’re right—just when things get unbearable, Yu lets you laugh, then yanks the floor away again. Sleep as a Weapon
Yu’s smartest move is treating sleep itself as the monster. Sleepwalking isn’t just a plot device; it’s the film’s central horror concept. We all have to sleep. We all surrender control. Now imagine your partner doesn’t just snore—they become something else. That primal vulnerability is what the movie keeps poking with a sharp, nasty stick.
Multiple reviewers have noted how Sleep taps into a universal fear: that the safest place in your life—your bed, your home, your marriage—might be where the real danger lives. The nights blur together, each one a new experiment in “what will my husband do while unconscious,” and the audience is dragged along with Soo-jin into that sleepless fog.
Science, Superstition, and the Horror of Not Knowing
Another delightfully cruel touch is how the film pits medicine against the supernatural and then refuses to pick a side. The doctors talk about sleep disorders, stress, and neurological explanations. The shaman talks about spirits, curses, and the need for ritual. Soo-jin occupies the miserable middle ground of someone who just wants an answer that will stop her baby from dying in the night.
Polygon praised how the movie walks a “delicate tight-rope” from grounded realism into increasingly desperate, supernatural-seeming solutions, all while keeping you unsure what’s actually happening. Is Hyeon-soo possessed? Is Soo-jin unreliable? Is this all trauma, hormones, and lack of sleep? Yu keeps that ambiguity alive right up to the end, which makes the final act land like a punch to your already frayed nerves.
One Apartment, Infinite Dread
As a formal exercise, Sleep is impressively tight. Critics have praised Jason Yu for “efficiently using a single location with endless storytelling possibilities,” and it shows: every room in the apartment gradually acquires a psychological charge. The hallway becomes a danger zone, the bedroom a crime scene in waiting, the baby’s room a shrine to anxiety.
The camera placement and sound design do a lot of heavy lifting. A creak in the dark, the off-screen shuffle of bare feet, a door that’s just slightly ajar—Yu understands that for exhausted parents, those sounds are scarier than any orchestral sting. The film feels both small and huge at once: we barely leave the apartment, yet the emotional stakes are enormous.
Lee Sun-kyun’s Quiet Goodbye
There’s an unavoidable melancholy in watching Lee Sun-kyun here, knowing he died in December 2023 and this stands as one of his final performances. It’s almost too fitting that his character is a man being pulled between versions of himself—loving partner, struggling actor, maybe-possessed sleepwalker—while his wife tries desperately to hold onto who he really is. The film never exploits that knowledge, but it does add an extra chill to his more vulnerable moments; the fear of losing someone you love to something you can’t see or fight hits a little harder.
Tiny Quibbles in a Strong Nightmare
If there’s a knock to be made—and horror fans will find something—that’s in the third act, where the escalating chaos flirts with repetition. There are only so many ways to stage “night falls, weird stuff happens” before you start to feel the pattern. A few critics wished the movie spent even more time in its shamanic weirdness or pushed harder into outright surrealism. But honestly, these are luxury complaints. The film’s 95-minute runtime is lean, and its focus on two people slowly breaking under pressure keeps it from ever drifting into anthology-territory bloat. It’s like a very stressful bottle episode that someone accidentally turned into an instant K-horror classic—Entertainment Weekly literally slotted it among the best Korean horror films of all time.
Final Verdict: Lose Sleep, Gain a Favorite
Sleep is that rare horror film that works on three levels at once: as a tightly engineered genre piece, a darkly funny send-up of new-parent panic, and a surprisingly tender portrait of a marriage under siege by forces seen and unseen. Jason Yu’s debut has the confidence of a veteran, juggling tone and tension with the kind of control that makes you curious—and a little afraid—of what he’ll do next.
It may not help you rest easier, especially if you already side-eye your partner’s snoring, but as a black comedy horror about the terror of sharing a bed with someone you love, it’s pretty much perfect. Watch it with the lights off, the baby monitor on, and just enough dark humor to laugh at the nightmare… at least until you hear footsteps in the hallway that aren’t supposed to be there.
