Making a film out of Maurice Sendak’s fragile, wafer-thin 1963 children’s book would have been a challenge for the most conventional filmmaker, but what Spike Jonze, who hardly fits that description, has done to “Where the Wild Things Are” is something remarkable—though not always in a good sense. Jonze has taken the beloved illustrated text and turned it into something like a twenty-first century version of an old Sid and Marty Krofft TV show—specifically a dark, edgy version of “H.R. Pufnstuf” (the plot—such as it is—has a very similar outline, and, the dominant “wild thing,” Carol, even looks like the mayor of Living Island gone to seed).

But at the same time Jonze’s take on the book is as faithful as it can be, preserving essence of Sendak’s original, which can only be read as a quasi-Freudian parable of a boy confronting the reality that he must finally stop gratifying his most primitive instincts, the id if you will, and begin the process of maturing into a socially-conscious person. That sounds like an awfully heavy load for a children’s book to carry (and it probably explains why Sendak’s classic was always appreciated more by adults than the kids at whom it was ostensibly targeted), and it’s equally so for the movie (which will probably also find more admirers among grownups than youngsters). And in realizing their vision, Jonze and his collaborators have shown a good deal of imagination, even if it sometimes takes a debatable turn.

But one of the picture’s greatest strengths is undoubtedly the performance of young Max Records as the central figure, a troubled nine-year old also named Max. It’s difficult to tell whether the incredible honesty of his performance is due to a natural expressiveness or careful coaching by Jonze, but the boy is a real find, capturing the character’s quicksilver changes of mood with uncanny authenticity and becoming a genuinely moving figure.

Records is at his very best in the opening reel, which sets up his unhappy home life. His single mom (Catherine Keener) doesn’t have as much time for him as he’d like, due to her job and a boyfriend (what amounts to a cameo by Mark Ruffalo), and his older sister (Pepita Emmerichs) is too busy with her friends to play with him. So he’s usually off alone, building forts and igloos and imagining battles; and in school his teacher regales the already morose kid and his uncomprehending classmates with tales of a dying sun that will mean the end of human life on earth. Things come to a head one night when he goes totally out of control at home, biting his mother and running off in his tattered wolf’s suit.

That represents a change from the book, in which Max is sent to his room, which magically turns into a forest. Here he scampers to the docks and climbs aboard what appears to be a real skiff and, after a treacherous voyage, reaches the island where the Wild Things live—Carol (James Gandolfini), his standoffish quasi-romantic interest KW (Lauren Ambrose) and serious best friend, the birdlike Douglas (Chris Cooper), the couple composed of sweet Ira (Forest Whitaker) and sharp-tongued Judith (Catherine O’Hara), and the mournful goat Alexander (Paul Dano). At first they threaten to eat him, but the puckish boy persuades them that he’s a Viking king, and has special powers that can ward off loneliness and sadness. Whereupon the creatures abruptly accept him as their ruler, and he proceeds to lead them in such rousing activities as fort-building, dirt-ball fights and simply rampaging through the woods.

The Wild Things, of course, are meant to be understood as creations of Max’s vivid imagination and as the realization of his longing for playmates. But they’re also representations of his own childish, violent impulses, quick to take offense and do injury and prone to destroy without any thought. As depicted by Jonze and co-writer Dave Eggers, they’re half-animal, half-human, and through his interaction with them (especially the volatile but sensitive Carol) Max perceives himself and learns to appreciate what he has back home, where, like Dorothy in “The Wizard of Oz,” he returns a changed and wiser person.

That’s all clear enough, but clarity isn’t everything. One also needs some narrative drive, which is where “Wild Things” stumbles. The rambunctious episodes on the island are all engaging enough—even if Lance Acord’s cinematography too often opts for jittery, blurry hand-held movement to jazz up the sense of excitement and the score by Karen O and Carter Burwell tries entirely too hard to be different, with its strumming rhythms and periodic resort to bland tunes. But the structure is chaotic, and while that’s perhaps intentional—reflecting the start-and-stop tendencies of a boyish mind—it doesn’t make for the sort of story arc that would tie the sequences together. As a result the picture tends to just ramble, often slowing to a crawl before revving up again. That gives it a rather limp, unfocused feel.

And the Wild Things themselves are a problem. It was probably the right decision to eschew pure CGI versions of them; having real people clomp about in costumes designed by the Jim Henson’s “Muppets”-inspired design shop has a homely charm, while the CGI element providing the facial expressions make for a good mix of old and new. But “fleshing out” their characters in action and dialogue doesn’t work as well as one might hope. As Jonze and Eggers portray them, they’re basically a squabbling, dysfunctional family in which Carol is the Max equivalent, despite his size. And the more they talk, the less wild and the more depressed and pathetic—and frankly less engaging—they become. Though the actors playing them all do yeoman work, they can’t solve what becomes an intractable problem.

The lack of narrative cohesion and disappointing creature characterization ultimately relegate Jonze’s labor of love to the status of a near-miss, despite its many virtues, not least the stunning performance by Records at its center. One appreciates the mixture of fidelity and imagination that Jonze has lavished on Sendak’s little book, but in the end the magic spark that marks a classic eludes him. And if the tepid reaction of the kids in the preview audience is any indication (they laughed mostly at scenes of characters falling down, slamming into trees and walls, and being smacked with dirtballs, but otherwise seemed turned off by the picture’s deeper, darker currents), his intriguing but problematic take on “Where the Wild Things Are” is unlikely to prove a fun family outing.