In Tokyo Tribe, all the characters rap. Almost all the time. And not very well, it has to be said, the actors not so much spitting rhymes as grogging them up in a clunky monotone. Fifteen years ago – around the time of Ichi the Killerthat might have seemed original and funny, but in 2015 the idea of Japan as a storehouse of weird post-modernity has been well codified. From a turntablist granny to a Yakuza with human furniture, there’s fun to be had here, but the wackiness also feels familiar and occasionally boring.

Visually ingenious, the camera floating about in long, woozy takes, Tokyo Tribe is otherwise a mess of flashbacks, sub-plots and misogyny that exhausts more than it baffles. It’s surprising that director Sion Sono has been around since the 80s, because this feels like a sophomore work: technically adept, but sketchy with narrative. When in doubt, he steals from Akiraa near future Tokyo carved up by teen gangs – alongside the sex jokes and violence of Takeshi Kitano, all overlaid with stylisation that fans of Zack Snyder might appreciate.

Amongst this borrowed decadence, there’s a message – one that any man who’s looked in envy at a friend’s massive penis will understand. Daft though that sounds, it’s the only genuinely unexpected thing in the whole picture, and almost rather sweet. If all the chaos onscreen seems to have sprung from the fantasies of a fourteen-year-old boy, then the secret anxiety that motors it comes from the same place. That’s more wearying than it is enjoyable, however, and as the film clatters to a halt, you want to tell everyone involved, especially the middle-aged Sono, to grow up.

For a movie about young people to make you feel so old – well, that’s not right.