A Minecraft Movie immediately creates a sticky paradox for itself. Clearly hoping to follow in the footsteps of a project like The Lego Movie, this video-game adaptation wants to pay tribute to the open-world flexibility and creativity of Minecraft while staying well within the framework of the game itself, which means including all of the expected blocky visual touchstones and including an obligatory number of cutesy gamer in-jokes. The surprise of the movie is how long it’s able to delay the latter material – long enough, it turns out, for Napoleon Dynamite director Jared Hess to get his foot in the door, expertly adapting his deadpan comic-strip style for a children’s fantasy.

Hess’ foray into big-time franchise filmmaking reunites him with Jack Black, the star of his 2006 slapstick adventure, Nacho Libre – and no one can accuse Black of half-assing his way through a paycheck job here. As Steve, a man who “yearned for the mines” as a child and discovers a portal into the magical Overworld as an adult, he throws off the shackles of workaday existence with such relish that his torrent of movie-opening narration feels enthusiastic, rather than blandly explanatory. The short of it: Bad-guy pigs covet the “orb” (like everything else in the Overworld, it’s block-shaped, not an actual orb) that Steve has discovered, so he sends his faithful wolf-dog, Dennis, to hide it in the real world.

Hess really connects with his Dynamite roots – throwback fashions, drier-than-dry non sequitur – and setting in that real world, where he pauses Steve’s story to follow siblings Natalie (Emma Myers, from Wednesday) and Henry (Sebastian Hansen) as they relocate to a small town in Idaho. There, creative, school-age misfit Henry clicks with Garrett Garrison (Jason Momoa), a former gaming champion who now runs a retro pop-culture junk store on the verge of foreclosure. Natalie, meanwhile, meets Dawn (Danielle Brooks), a friendly real estate agent who moonlights as a kind of mobile zookeeper.

In a movie for grown-ups, this litany of quirk might seem a bit much: Natalie is a young woman of indeterminate age who gets a job running social media for a local potato-chip factory; Henry tinkers with his design for a working jetpack. For a kid picture, though, it’s sweetly silly, even distinctive; the kitschy tater-tots-and-alpacas ambience is pure Hess. Momoa in particular makes a surprisingly good fit for the filmmaker’s sensibility, playing a less bullying version of the blustery Napoleon Dynamite sensei Rex Kwon Do. In fact, the first 30 to 40 minutes of A Minecraft Movie have enough big laughs that it’s almost a disappointment when Henry, Garrett, Natalie, and Dawn stumble upon the orb and wind up accidentally sucked into the Overworld.

Eventually they meet up with Steve, who provides some standard gameplay tutelage in advance of their quest. The quest itself is conceptually muddy, confusingly and erratically presented as some combination of saving Steve’s beloved Dennis, protecting the orb, and eventually bringing the four displaced travelers home. The seams of the six-writer screenplay show frequently, like when characters make plans and then deviate from them without comment as if the actors are all working from different versions of the script. Based on the uninspired action sequences – digital hordes running and flying around in a manner better suited for an in-game Lord of the Rings fan film – there aren’t many big-budget fantasy epics in Hess’ future. But A Minecraft Movie stays light on its feet nonetheless by continually pausing for slapstick silliness and cartoonish little sketches like an ongoing and delightfully pointless subplot involving Jennifer Coolidge and a resident of the Overworld.

Eventually, the more antic side of things takes over, and the various CG landscapes populated by blocky people and creatures start to feel repetitive. It’s like a slightly more polished version of someone’s playthrough video, only with a couple of big stars getting thrown around the screen. What A Minecraft Movie misses from Minecraft the game is its combination of minutiae and vastness; as much as the movie advertises its subject’s creative flexibility, it shortchanges any potential obsessiveness in favor of making the Overworld look a little more like something out of a Mario game. The parallels to Black’s other video-game-movie gig – and aspirations to its popularity with the playground set – become especially clear when Steve chases the next “Peaches” by riffing out no fewer than three little songs. (On the other hand, it’s hard to resist Black bringing his goofball-rock-star shtick to Gen Alpha.) As with so many game-based movies, the mismatch between what each medium does best isn’t really reconciled by A Minecraft Movie. But turning the world’s best-selling video game into Jared Hess’s best feature in years is, admittedly, a pretty creative undertaking.