Paranormal Activity: 'A visceral sense of dread'

People screamed. They hugged each other. Popcorn went everywhere. At least half a dozen punters walked out, and when lights finally went up, a shell-shocked auditorium reverberated with a collective sigh of relief.

If you judge a movie by its ability to deliver on a promise, then Paranormal Activity, which has no ambition more lofty than to scare the living bejeezus out of you, has to go down as an unqualified success.

Set entirely at the San Diego starter home of a young day-trader called Micah (Micah Sloat), and his girlfriend Katie (Katie Featherstone), its story is told through shaky camcorder footage that was apparently shot by the fictional couple, in an effort to document things going bump in the night.

Katie was troubled by the paranormal during childhood, we soon learn. A ghost, or demon is now haunting her in the dead of night. Micah, at first sceptical, becomes gradually more curious, and then aggressive towards the apparent imposter under his roof.

The subsequent terror, for there can be little doubt that this film is terrifying, is largely implied rather than forced – and better for it. Doors slam, for no reason. Lights flick on and off. Footsteps tiptoe along landings. Fear lurks behind shower curtains and patio doors. Violence is suggested, but rarely played-out.

Though entirely filmed with handheld camera, which lends Paranormal Activity the claustrophobic and sometimes nauseating appeal of The Blair Witch Project, the film also owes a debt to classics of the horror movie genre such as The Exorcist, and the early Poltergeist movies.

Marketing is, of course, central to its eerie appeal: watched in a half-empty cinema, parts of Paranormal Activity could fall flat. But at a packed midnight screening, sandwiched between gasping filmgoers, it feels impossible to escape its sheer, visceral sense of dread.