Diary of the Dead, 18

In the recent Cloverfield, a character uses a camcorder to record a monster trampling Manhattan to dust. You can't help asking, why not drop the camera and run for dear life? Because then there wouldn't be a film. It's just not a pertinent question. In Diary of the Dead, however, it's the central question. Why film when a plague of zombies makes it questionable whether anyone's even going to be around to see your footage?

Horror maestro George A Romero has been making his zombie apocalypse dramas intermittently over five decades, starting with the still chilling Night of the Living Dead (1968). Ghoulishly entertaining, but with a distinct satirical agenda, Romero's zombie chronicle has offered an ongoing critique of the United States: his last episode, 2005's Land of the Dead, suggested that America's future belonged not with the corrupt living, but with the dead themselves, portrayed as a beleaguered multi-racial underclass.

It was a vision of nothing less than American proletarian revolution.

With the low-budget Diary of the Dead, Romero goes back to basics, and to square one: as the film begins, the dead are just starting to come alive. The premise is that we're watching a video diary, presented in voice-over by Debra (Michelle Morgan). At the start, her film student boyfriend Jason Creed (Josh Close) is shooting a horror pic, and Romero amiably parodies his own bargain-basement origins – "Not run, shamble!". When the real revenants start shambling, Jason turns from fiction to documentary, determinedly filming the escalating horror.

As in Cloverfield and The Blair Witch Project, the camcorder device reminds us that horror is as much about what you can't see as what you can. The limited vision provided by a camera operator who's possibly being stalked in the dark while trying to film whatever's stalking him – that's a perfect recipe for chills. Romero plays this angle brilliantly, but also has typically grisly fun with the stuff that you can see all too well.

After all this time, his body-shock gags continue to be horridly witty. A farmer uses a scythe in a spectacular gesture of self-sacrifice; zombies are impaled, melted with acid, have their eyes pop out from electric shocks.

A zombie clown even has its nose pulled off, and it's a measure of Romero's brilliance that he merely suggests that gag's unthinkable pay-off, cutting away when a sickster like Eli Roth would have hovered.

But behind all this lies Romero's interest in the breakdown of the establishment. Typically, a living detachment of National Guards proves to be as much of a menace as the dead, while a new order is represented by a black paramilitary group ("For the first time in our lives we got the power. Everyone else left.") The media mainstream collapses helplessly. At the start, a TV news team gets killed by its own story; later, Romero shows the same footage re-edited by the channel in a desperate gesture of damage limitation. Official media coverage becomes white noise over images of carnage; in the middle of one montage is a close-up of George Bush's helplessly jabbering mouth.

Responsibility for telling the true story seems to rest with Romero's beleaguered young film-makers and the internet community they communicate with. But are they doing the right thing, or just seeking protection behind the lens, losing all sense of moral reality as they do so? Debra seems to be the film's moral conscience, but no one is immune. She rages against Jason's morbid camera fixation, then turns round to film someone's guts tumbling out. Beyond the macabre fun of it all, Romero's concerns are ethical, and he's asking an urgent question about contemporary image culture: are we filming ourselves to death?