IN 1981, IN MILPITAS, California, a 16-year-old boy raped and murdered his girlfriend. Over the next few days, he took friends on trips to see her corpse, left lying by the riverbank. For a long time, none of them thought to call the cops.

Dressed in grungey death-metal chic and transposed to Oregon’s grey suburban haze, the basic facts of that case served as a leaping-off point for 1986’s River’s Edge, one of the most significant movies to address the growing numbness of Generation X?and also, conversely, one of the most disconcertingly entertaining.

Written by Neal Jiminez, Tim Hunter’s movie begins with John (Daniel Roebuck, a blubbery, beer-swilling blank) sitting by the girl he’s just strangled. He mentions to sceptical high-school friends he’s killed her, then leads them to the body. No one seems to feel much? except self-appointed leader of the pack Layne (Crispin Glover). He feels something: like he’s in a movie, “like Chuck Norris”, and although no one else, least of all John, cares, he begins riffing on his fantasy, urging everyone to save their buddy from being caught.

River’s Edge is like two films slammed together. On one hand, with its often overly emphatic messaging, and Keanu Reeves and lone Skye Leitch holding hands as the most sensitive members of the gang, bothered by the vague sensation something’s not right, it’s like a bleaker-than-usual John Hughes lost-teen flick. On the other hand, though, there’s Dennis Hopper as a melancholy, one-legged, drug-dealing ex-biker with a blow-up sex-doll for a soul-mate, and Glover ripping scenes apart with his hysterically anti-naturalistic Valley Boy speedfreak act, treating the whole thing as expressionistic comedy.

That unsettling discordance is, presumably, why David Lynch subsequently hired Hunter to direct episodes of Twin Peaks (another story of small-town teen secrets and a pale girl dead by the river) and, 18 years on, it’s what keeps River’s Edge so strangely alive. That and its chill prescience; in the portrayal of Reeves’ 10-year-old brother Tim (the demonically androgynous Joshua Miller) the movie seemed certain of one thing: the next generation would be even number. He’s the sort of kid who grew up to go to Columbine.