George Romero's Land of the Dead, the fourth in his series of much-loved, much-imitated zombie gore-fests, previews at London's Frightfest this evening. How times have changed. In 1968, as a struggling rookie film-maker in Pittsburgh, he was putting together Night of the Living Dead on a shoestring, persuading friends and family to dress up as reanimated corpses and tear apart piles of entrails. In 2005, his new film was shown at Cannes to a standing ovation. Now horror is the most consistently popular genre at the US box office, and it's big business. But is money dulling its edge?
For those who like their horror rough, ready and covered in cheap blood-effects, there seems to be a lot to mourn. In the late Sixties and early Seventies, film-makers ditched the high camp of the Hammer style and set out seriously to scare their audiences. A new era of realism was ushered in; fear wasn't confined to vampires' castles in Transylvania - it could strike anywhere. Romero was one of the foremost innovators. His Night of the Living Dead, made as America was being shaken for the first time by its losses in Vietnam, reveals a country at war with itself as much as with invaders. Seven human survivors are holed up in a farmhouse surrounded by a horde of zombies, but these are not your traditional heroes. Their mistrust and petty betrayals of each other are more of a threat than the cannibals outside, who have, after all, no choice as to how they behave.
Dawn of the Dead, made in 1978, continues the theme. Here, the protagonists hide out in a mall, and end up fighting, not the zombies, but other survivors, for possession of their consumer paradise. Day of the Dead, too, made in 1985, critiques the growing militarism of the Reagan era by pitting scientists and soldiers against each other. Horror, it seemed, was now in everyone's backyard and no one - not even the hero - was guaranteed to survive.
Other film-makers took note. Tobe Hooper's The Texas Chain Saw Massacre, from 1974, was the original teens-in-peril story; Brian De Palma's Carrie, adapted in 1976 from a Stephen King novel, reminded us that even school bullies have no place to hide; in Halloween (1978), John Carpenter brought terror to surburbia. With the innovative storylines came innovative effects. The make-up artist Tom Savini, who worked with Romero on his Dead trilogy, used his experiences in Vietnam to recreate wounds, blood and gore more realistically than they had ever been before. And then Steven Spielberg brought new trickery to Poltergeist (1982), terrorising a middle-class family with animated clowns, haunted mirrors and ghosts in the television.
But this marriage of innovation and money couldn't last; horror was split. On the one hand, directors like Sam Raimi, Dario Argento and Peter Jackson kept true to the original, anything-goes, low-budget vision. On the other, producers realised that killing off teenagers was bringing in big bucks. They saw a winning formula and stuck to it, over and over again. Carpenter's Halloween, Friday the 13th (1980), Wes Craven's A Nightmare on Elm Street (1984) and even Clive Barker's Hellraiser (1987) were followed by increasingly shoddy sequels. For continuity's sake, major characters were guaranteed to survive the bloodiest holocaust; the element of surprise was lost. Horror had turned into a parody of itself, a fact acknowledged by Craven's knowing, witty Scream (1996), in which his teenage characters - all horror fans themselves - try to work out where the killer will strike next.
But just when it seemed that horror had nothing more to offer, a startling - and terrifying - series of films burst out of Japan. Hideo Nakata's Ringu (1998) ditched the knowingness and brought fear back into the heart of the household, via the television. A vengeful ghost frightens her victims to death by means of a haunted videotape. Ju-on, another old-fashioned ghost story, followed in 2000.
As with the best films of the Seventies, of course, Hollywood saw dollar signs and leapt on the bandwagon. Ju-on was remade as The Grudge with the teen queen Sarah Michelle Gellar; Ringu as The Ring with Naomi Watts
But you can't keep a good genre down, and as fast as one trend goes mainstream, another springs up to take its place. The UK director Neil Marshall went back to things-that-go-bump-in-the-night basics for Dog Soldiers in 2002, and terrorised a group of potholers in The Descent, released this July. The Australian film Wolf Creek, which will premiere at Frightfest, moves the unfriendly locals of The Texas Chain Saw Massacre to the outback.
The horror commentator Kim Newman says that horror is in an exciting place right now, remakes or no remakes: "They may be reductive," he says, "but for their audience they're surprisingly effective. Maybe there's a horror movie for everyone." And perhaps that's the point: as long as a movie is scaring someone, it's doing its job. Like one of Romero's zombies, it seems, horror just won't stay dead.
Frightfest runs to 29 August at Odeon West End, London W1 ( www.frightfest.co.uk); 'Land of the Dead' is out on 23 SeptemberReuse content