Whether letting Bruce Willis loose on terrorists who've hijacked an airport in "Die Hard 2", or capturing the antics of Sly dangling off huge mountains in "Cliffhanger", Renny Harlin has turned into the kind of all-action film director who has no trouble abandoning logic in favour of big thrills. He generally hopes that by leaping from tense scene to tense scene, no-one will notice the massive cracks in the script. And he's done it again.

In "Deep Blue Sea", medical scientists on a partially submerged facility far out to sea are using sharks as guinea pigs in a search for a cure to Alzheimer's disease. Their experiments have produced highly intelligent sharks, which are also very big. Keen to leave the confines of the facility, the sharks soon turn on the scientists, intiating chaos, destruction, and of course, feeding.

Thin characters spout idiotic lines, with only Samuel L Jackson having any real screen presence. LL Cool J gets what little witty dialogue there is and to his credit, makes the most of it. Harlin, taking his cue from all other action directors today, ensures that your skull shakes with noise as the research facility breaks apart and the sharks close in on the survivors.

And yet, despite scene after scene of mayhem, Harlin manages to create and and sustain extremely well-coiled tension. This is his real strength and he is consequently able to distract you from your first instinct, which is to laugh, and push you towards the edge of your seat. If he could only marry this strength with imaginative scripting and solid characterisation, not to mention the odd quiet moment, he would certainly move out of cartoon corner.

Read a review of the DVD.