Shocking to think, but there hasn't been a decent shark movie since Spielberg and Bruce bloodied the brine back in 1975. Still, even Jaws' risible sequels and blockbuster fodder like Deep Blue Sea made a box-office splash. Why? Because sharks remain one of the modern world's most potent symbols of death. Forget Freddy Krueger and Michael Myers. These are the real-life horror stars: dead-eyed killers ready to flip-flop the food chain with a single, razor-toothed thrash.
Cutely pitched as Jaws meets The Blair Witch Project, Chris Kentis' lo-fi lost-at-sea chiller mainlines this feral fear with almost unbearable intensity. It's certainly slow to get rolling, our wittering couple pushing the patience as they soak up the tourist locale and swap inane chit-chat. But stay awake and you'll notice the loaded hints: a smiling plastic shark here, coils of rope hanging like nooses over there. And once we hit the water, things get seriously scary. See, Kentis couldn't afford CG fin-wigglers or clunking robo-monsters. So he used the real thing - and lots of 'em.
This suffocating horror-verité is what gives Open Water its mojo, Kentis' tight, queasy DV framing wringing every drop of sweat from his slight survival story. With Susan and Daniel shivering in the water as grey predators flash in and out of sight beneath them, constant dread threatens - practically every second - to spike into heart-stopping terror. It's hard to remember a more intense riff on the horror genre's favourite sadistic game: they can see you, but you can't see them...
Of course, even 80 minutes is a long time to point a camera at this stripped-down set-up. Thankfully, though, Kentis' script and his bobbing actors fill the lags with a much-needed human pulse, their nervy wisecracking and marital bickering ("I wanted to go skiing!") made all the more funny by the life-and-death backdrop.
It's inevitable that, with so much pinned on the unknown, much of Open Water's impact evaporates on second viewing. But one-watch fear-flicks don't come this well executed that often. So cancel that scuba holiday and bring your rubber trousers to the cinema instead. You'll need them.