In the broad plot details, Andrés Muschietti’s 2017 Stephen King adaptation It is astonishingly close to Rob Reiner’s 1986 Stephen King adaptation Stand By Me. In both movies, a group of pre-adolescent kids run around the outskirts of a small town, bonding during the long summer days and nights. In both movies, one of those kids has a terrifying abusive father; another has recently lost a brother, and his shell-shocked parents have mostly abandoned him to his own devices.

The child protagonists in both Stand By Me and It are outcasts and nerds, largely ignored and forced to find comfort in each other. They’re all hunted by a pack of ferocious, dangerous bullies — bigger kids who are bored with their sleepy town, and victimize other people for entertainment. Both groups of kids set out to look for a corpse, and along the way, they become each other’s emotional support, with all the idealized intensity and simplicity Stephen King always puts into evoking childhood. And both films are openly coming-of-age stories, about the last days of innocence before unwanted adult realizations and responsibilities set in.

But only one of these movies has the kids facing a shape-shifting killer clown.

In Stand By Me, the only real monster is death itself — the sudden understanding, brought on by a child’s corpse, that childhood doesn’t last forever, and even kids can die. In It, the child corpses pile up early and often, and an understanding of death is baked into the world — especially into the town of Derry, Maine. The film’s first death occurs in its opening sequence, as a horrifying clown calling himself Pennywise (Bill Skarsgård) lures a little boy named Georgie Denbrough into a fatal trap. Months later, Georgie’s brother Bill (Jaeden Lieberher, from St. Vincent and Midnight Special) has become obsessed with finding Georgie’s body, and he leads his friends Ritchie (Stranger Things’ Finn Wolfhard), Eddie (Jack Dylan Grazer), and Stan (Wyatt Oleff) into trouble as they search the sewers for some sign of the boy.

Other children have gone missing as well. When the group, eventually dubbing themselves The Losers’ Club, hooks up with town new kid and amateur historian Ben (Jeremy Ray Taylor), he informs them that Derry’s murder rate is six times the national average, and kids disappear at an even higher rate. One by one, their group — plus token girl Beverly (Sophia Lillis) and token black kid Mike (Chosen Jacobs) — encounters Pennywise in different monstrous forms tailored to their personal fears. Soon, they understand that Derry’s adults won’t do anything about It, and it’s up to them to fight back.

The “encountering Pennywise one by one” dynamic gives It its biggest problems. Director Andrés Muschietti and his writers (Chase Palmer, Cary Fukunaga, and Gary Dauberman) stick close to King’s massive 1,200-page novel, porting in his dialogue where they can, and adding in-jokes and Easter eggs to acknowledge where they skim over King’s bigger, harder-to-convey elements. They ditch the vision-quest encounters with the cosmic turtle who created the world, but as a wink-wink move for audience members in the know, they throw in visual and verbal turtle references. They also drop the ridiculous child-orgy, while acknowledging the themes of rite-of-passage and sealed personal intimacy behind it.

But inevitably, slimming the story down to a 135-minute run time involves cutting a lot of individual character time, to the point where several of the Losers blend together. Some abrupt, confusing edits suggest a longer version of the story where the more neglected protagonists get more screen time, but as it is, Stan’s entire characterization is “Jewish kid with bar mitzvah approaching,” and Mike’s is “black kid who lives on a farm.”

And not knowing all of these characters well means not understanding what scares them, and why it should scare the audience, too. Beverly is one of the better-developed Losers, and her fear of puberty and menstruation — driven by her abusive father, who sees her physical development as a threat to his control — gives It one of its eeriest moments. Her bloody encounter with Pennywise closely recalls images in two other famous King screen adaptations, Stanley Kubrick’s The Shining and Brian De Palma’s Carrie. It’s a primal sequence, scary on its face, but also resonant with personal meaning for Beverly. It shows how It is meant to function, as a window into individual psyches, and into a monster that explores and exploits them.

By contrast, many of the other It encounters blur by in a repetitive wave of on-screen lunges and screams, provoked by CGI threats and the same imagery over and over. King’s It is a wandering, discursive book that spends plenty of time on the mechanics of what terrifies individual people, and the varied ways they respond to that terror. The idea of a shape-shifting monster that taps into its victims’ fears is unbeatably personal and flexible. Both King and Muschietti use it to great effect, haunting the characters with jittery walking corpses and a twisted Modigliani-style painting come to life. But there are seven kids in the Losers’ Club, and all seven of them have to have jump-scare-filled personal encounters with Pennywise. Then they start hunting It, and It isolates them and victimizes them separately again, with diminishing returns for both It and the audience. After a while, there’s just too much monster charging mindlessly at the screen, and not enough time to process the characters’ reactions, or to distinguish one curiously failed attack from the next.

But It has two major saving graces: Muschietti’s eye for striking images is one of the film’s core assets, and his ghost story Mama often comes to mind throughout It. Unlike most monster movies, which withhold their central critters until the end to build up suspense and mystery, Muschietti put Mama’s monster on-screen early, and trained viewers to fear her for her unsettling eeriness and malice. He does the same with Pennywise, leaving any sense of mystery and dread out of the film, but replacing it with sharp shocks and Uncanny Valley creepiness.

And the convincing child cast carries the film when the scares start to feel redundant. Jeremy Ray Taylor and Sophia Lillis are particular standouts — as the smart, fat kid with a crush, he’s surprisingly tender and nuanced, and as the tough girl with an unpleasant secret, she’s close to heartbreaking. But all seven of the central children are well-cast and give strong performances, and seen through their eyes, Pennywise seems like a real threat — a childhood nightmare improbably manifested in the real world — instead of like the faintly goofy, try-hard boogeyman he could so easily be.

Still, it’s easy to wish for a more Stand By Me-like approach to It. Rob Reiner’s King adaptation is far from perfect, but without a monster haunting the kids, it has much more leisure time to explore their personalities and problems, to dig into their individual relationships and show how not all friendships are created equal. Both films take up King’s obsession with nostalgia and the past, with the connections between youthful trauma and adult behavior, and with the abrupt, startling exact moment when childhood ends. It does all these things bigger, louder, and spookier, with the equivalent of a sustained shriek at the audience. But even the loudest shriek stops being scary after two hours. Muschietti is already planning a sequel — the second half of King’s book, heavily foreshadowed in this film, where the scattered Losers return to Derry to face Pennywise as adults. With any luck, that half of the story will take a little more time to breathe in the fears it evokes, and take the time to appreciate their impact as much as their imagery.