13-year-old Josh Baskin (David Moscow) yearns to be big and learns the misery of adulthood when he wakes up as a full-grown George Osborne lookalike (Tom Hanks).

Directed by Penny Marshall (A League of Their Own), written by Gary Ross (Ocean’s 8) and Anne Spielberg (Steven’s sister), and lensed by Barry Sonnenfeld (the Addams Family movies), Big was huge in 1988 but has aged as quickly as Josh does in the movie. Combining body-swap comedy (without the swap) with corporate politics and questionable sexuality, this is one of those tonally bizarre ’80s films that’s meant to be heartwarming but is just plain weird.

It starts amusingly enough, with Josh’s mother (Mercedes Ruehl) freaking out at the sight of a strange man in her house claiming to be her son. We could forgive the plot holes (why the Hanks character isn’t treated as suspicious by police, who teaches him to shave, where he gets his clothes etc.) if the story maintained the fun of the famous Walking Piano scene, instead of getting bogged down in strangely serious and involved work and relationship drama.

Josh uses his gaming experience to get hired by a toy company (back in the 1980s you could wander in off the street and get a job in computers) and sleeps with his real adult colleague (Elizabeth Perkins), who ends up worryingly unperturbed about having had sex with a child. This combines Mannequin/Weird Science boyish sex fantasy with the genuinely dark Forrest Gump/Elf idea that women become jaded to the point of being attracted to men who are mentally children, which probably wouldn’t be acceptable the other way round.

The other Hollywood trope in play is that of an imbecile stumbling blindly into a position of influence (Forrest Gump, Being There), which presumably seemed aspirational but now appears to be a damning indictment of American culture or a Trump-era prophecy. The obliviousness of Josh’s colleagues and girlfriend reads almost like an American Psycho-style satire of ’80s corporatism, without the ironic pop soundtrack (Howard Shore provides the mawkish score).

Awkwardly for a comedy, the film deliberately gets more depressing as it goes along as a warning to not grow up too fast. It has a strong central performance (adult with a child’s brain was Hanks’ speciality) and metaphorical core (aren’t we all Tom Hanks in Big?), but even as a celebration of childhood Big is oddly unimaginative. Its idea of play only involves branded toys so its childish spirit is couched in consumerism, albeit more insidiously than Jingle All the Way.

This is a nauseating movie on a number of levels, simultaneously schmaltzy, unhappy and icky. The unholy mixture of childish premise and several fucks (the word and the act) makes for a creepy sex comedy, or family film as they were known in the ’80s.