Here’s a movie that is heading somewhere interesting but never quite makes it: a nerd comedy co-written by and starring Saturday Night Live’s Kyle Mooney. He plays James, who was abducted as a toddler by two crazed educationists who kept him hidden in the house all day, and made him watch an endless stream of VHS tapes, episodes of their own bizarre home-filmed fantasy epic, Brigsby Bear, a story with ethical and mathematical lessons.

Poor James has grown to adulthood as the show’s No 1 fan, poignantly believing Brigsby Bear to be a global smash with millions of viewers. But when he is discovered, freed and returned to his family, James must come to terms with the fact that he is the only person who knows about Brigsby Bear. But then he uploads these Brigsby tapes online and Brigsby Bear gradually becomes a real success. Is this therapy or the perpetuation of abuse in an infantilised culture?

Brigsby Bear has resemblances to Galaxy Quest and also to Michel Gondry’s movies about fan culture and VHS fetish such as Be Kind Rewind and The Science of Sleep, but without those films’ genuine emotional charge and without Gondry’s rigour and detail. His captor is played by Mark Hamill, inevitably calling to mind the mythic world of Star Wars, but when a kindly local cop (Greg Kinnear) agrees to take part in James’s projected Brigsby feature film, it is his bearded, cloaked figure that resembles Luke from The Force Awakens. Could it be that Mooney once hoped that Hamill might play the cop role? As the film unwinds to a sentimental anticlimax, its potential is unfulfilled.