Buoyed by borrowings from The Poseidon Adventure, Alien and The Abyss, the leaky old aqua-thriller has weathered all the storms and doldrums which have beset the horror genre over the decades, and this is the best effort for some time. Harlin's movie may have a routine plot, but check out that gleaming marine research facility. Think hi-tech Titanic, and try not to worry about the practicalities. Burrows provides the unwitting comedy relief as a high minded scientist driven to cut corners in her quest to cure Alzheimer's by experimenting on (live) shark brains - the rationale being they don't age, or some such. This business about genetically modified 'smart sharks' with brains the size of a V-8 is priceless (maybe they should have had a go at the script), especially when the digital fx guys get carried away and work up a synchronised attack routine that would wow any Olympic committee. But if we're laughing at the movie: there's something very gratifying about the regularity with which Harlin cuts his cheesy characters down to size. And as a piece of cinematic engineering, it's nothing if not efficient.