Starring Sunny Suljic. Rated 18A

For his writing-and-directing debut, Jonah Hill skates across safe ground with a coming-of-age drama set during the era of his own adolescence.

It’s too safe, in fact.

Hill grew up in privileged circumstances, but he shows good instincts here, in a down-market part of Los Angeles where skate punks hang out for camaraderie and protection.

Stevie, an unformed 13-year-old played by Killing of a Sacred Deer’s Sunny Suljic (who looks like an 11-year-old Timothée Chalamet), worships his older brother, Ian (Manchester by the Sea’s Lucas Hedges). But the latter beats the crap out of him for disturbing his pathologically organized bedroom.

They have an uneasy relationship with their single mom (Katherine Waterson), not named in the movie or given a job or personal history—except when Ian complains that “She used to be promiscuous.” This vagueness haunts the whole enterprise, as little Stevie wanders into a multi-ethnic gaggle embodied by nonprofessionals who have board skills and some screen presence, but no real characters to develop.

The savvy black kid called Ray (Na-kel Smith) runs a local board shop, and he’s so cool he doesn’t even need a nickname. His pals include the persistently swearing Fuckshit (frizzy-haired Olan Prenatt) and taciturn Fourth Grade (Ryder McLaughlin), who’s slightly dim but documents everything with his Hi-8 camera. (Think his footage will show up at the end?)

There’s already a mascot on the scene, but brooding Ruben (Gio Galicia) soon sees himself displaced as the resident preadolescent.

The novice director lets the wisecracks flow naturally as Stevie is drawn into their knuckleheaded orbit. Scenes of him learning to skate and getting to know this subculture show a promise the film never quite delivers.

Hill resists his Apatow-bred instinct to go fully comic. But he doesn’t compensate with deeper insights that would make these commonplace personalities compelling in a dramatic sense.

Weirdly, both Stevie and his brother exhibit a propensity for ritualistic self-harm that suggests a traumatic history that isn’t explored or explained. As our pint-size protagonist turns into a mini-badass, he also has a sexual encounter with a much older girl (Brigsby Bear’s Alexa Demie), but it’s unclear how the filmmaker feels about any of this, or if he has any real interest in what’s going on in the heads of the few females present.

The movie is shot on 16mm in the old-fashioned squarish format, and it’s loaded with period music, of course.