While it doesn't solve the recurring problem that blights the found footage mockumentary – why don't they put down the camera? – The Dirties is a brave take on bullying and its consequences.

Teenagers Matt (Johnson) and Owen (Williams) are two movie-loving seniors who have been bullied by the titular gang so long it's just another part of their day. Passing off daily humiliation with laughs, Matt and Owen turn their situation into inspiration by making a short film for a school project, with the 'making of' documented by another student who remains unseen. Their movie – two detectives do a 22 Jump Street and infiltrate the school to shoot the bad guys – is a black comedy but when the bullying escalates Matt and Owen flirt with the idea of turning the plot into reality...

Written and directed by Matt Johnson, crafts a tender friendship between him and his co-lead Williams. Using improvised dialogue, there's a naturalness to their lived-in characters who behave like friends who have known each other for years would. It's believable. There's love there. And the one-hundred-and-one film references, some deliberately quoted out of context, will appeal to the movie buff in the audience.

But Johnson, looking younger than his twenty six years, waits until one gets comfortable before slipping in reminders that this is not meant to be funny or sweet - there is a real hatred bubbling just under the surface. It's during the sporadic bullying scenes, which barge in on the movie and take it over for their brief duration, that the laughs disappear and you're there with Matt and Owen during those confrontations in the canteen, in that hallway, at the locker. At one point Johnson is reading a book on Bowling For Columbine for tips and later reads out a paragraph about sociopathic personalities of the teen killers, wondering if the profile suits him. And then there's real moments of black comedy – Johnson giving himself a makeover montage of what to wear on the day of retribution. Is a Catcher In The Rye t-shirt too much?

But the issue of who is shooting and to what end isn't addressed. Once in a while Matt and Owen turn to the camera – 'You're going to have to put in the end credits' – but the cameraman isn't involved in the story. One kitchen scene suddenly cuts to outside the kitchen window looking in. Are there two cameramen? Three?

Warmer than the similarly themed but deliberately distant Elephant, The Dirties is one of the best teen movies of the last decade.