If 'broken-backed' can be a term of praise, Cheng's extraordinary DV feature earns it. Inspired by a banned novel by Mian Mian (who here plays Kika, a character not a million miles from herself), it offers a discontinuous panorama of the various panics that grip Shanghai's jeunesse dorée - the pampered, solipsistic kids produced by the communist government's one-child policy. The first half centres on HIV panic: disco boy Bei has a fever that won't subside, but won't go for an AIDS test because he's heard that China ships HIV+ people off to a prison island. He and his friends Kika, Fifi and Casper deal with the problem by clubbing even harder and taking even more 'E's and ketamine. The second half veers off into panic about sexual identity: Bei shacks up with his friend Jie in a borrowed apartment and tries to persuade him to have sex - although Bei denies being gay, and anyway has a thing for paedophile websites. Although it's fiction, every frame feels intrusively real: the benefit of asking a non-pro cast to act out their real lives and shooting it as a one-man crew. Very possibly the start of a new chapter in Chinese cinema.