When You Finish Saving the World review – Jesse Eisenberg’s sweet coming-of-age comedy drama

Jesse Eisenberg was Oscar-nominated for his fast-talking turn as Mark Zuckerberg in The Social Network – a performance that persuaded the world to think of the Facebook supremo as a garrulous, injured soul. He is also the author of accomplished stage plays, short stories and pieces for the New Yorker. Now he makes his feature film debut as a writer-director with a sweet-natured and well acted movie about Ziggy (Finn Wolfhard), an insufferable and naive teenage boy in high school, who preens himself on all the followers he has for his livestreamed folk-rock songs, with titles such as Truth Aches. His equally insufferable but idealistic mother, Evelyn (Julianne Moore), kindly, if overbearingly, runs a shelter for abused women.

Secretly hurt at the way her son has moved away from her into the world of lo-fi online celebrity – Ziggy has rigged up a big flashing red light outside his bedroom to warn his parents not to come in while he’s broadcasting to the fanbase – Evelyn befriends the bewildered teenage son of one of the women at her refuge. She tells her protege how to better himself and apply for college, “grooming” him as the obedient, grateful son she never had.

When You Finish Saving the World (the phrase is never used, but clearly enough conveys parental exasperation at pompous teens who lecture their elders on global issues without doing the washing up) is a movie with the indie, stonewashed look that its distributor A24 has virtually made a house style. It’s an ironic, knowing but fundamentally sentimental film, in the “coming of age” manner, whose emollient intergenerational comedy brings it very close to the gloopy world of Dear Evan Hansen. But however on the nose it is, however broadly predictable its comic beats and occasionally cartoony characterisation, it is watchable and sympathetic.

Both Ziggy and Evelyn have crushes on people who are unattainable. Lila (Alisha Boe) is a cool, smart person in Ziggy’s class, clued in on radical left politics, about which Ziggy is as innocent as a child, and he makes deeply misjudged attempts to talk about this in her presence, failing to read the room. But these are the politics that once animated his mother, in whom they have evidently declined and coagulated into that sort of white-saviour do-goodery that Lila would despise. Evelyn’s crush is on Kyle (a very good performance from Billy Bryk), a sensitive, mature boy who has moved into the shelter with his mom Angie (Eleonore Hendricks), and who has a biddable, friendly personality, which Evelyn bossily latches on to.

Evelyn and Ziggy are heading for life-lesson-learning broken hearts, and the film suggests that this is what is going to bring them back together. I think it only works for one half of the equation. It is plausible that the calamity of Evelyn’s project will bring her back to Ziggy, but in the real world Ziggy’s woes are likely to take him further still away from his family, the redemptive reckoning being more likely to happen much later in adult life. Also, the figure of Ziggy’s grumpy/reticent dad Roger (Jay O Sanders) is a little underwritten.

But the tricky mother-son relationship is well managed and Moore always brings to this kind of Oedipal drama a seriocomic intensity (as in Tom Kalin’s Savage Grace from 2007, playing opposite Eddie Redmayne). She has a nice scene where Ziggy boisterously yells a greeting from across the street and Evelyn, with schoolteacherly reserve, says: “I will speak when you are closer.” It is a symbolic moment for them both.

• When You Finish Saving the World screens at the Cannes film festival.