47 Meters Down

This low budget but highly-effective horror film is exactly the kind of movie that legendary Hollywood D-movie producer Roger Corman would have knocked out in the '70s: plenty of writhing female limbs, no surprises.

Even at 89 minutes, you can feel the oxygen running out of this movie.

It's gratifying to see a summer popcorn movie where a simple idea goes a long way.

It's taut and suspenseful, and there's a jittery vibe to the whole thing.

The movie's saving grace is the visceral response that sharks produce, even more than four decades after Jaws first had audiences screaming.

While the plot is a bit shaky in parts, the overall effect of creating needed tension and some outright, out-of-your-seat jumps of fright is quite effective.

British director Johannes Roberts, with good work from cinematographer Mark Silk, allows the undersea action to unfold like a procedural, so that the details ratchet up the tension.

It's not a great film but, once the preliminary scenes on terra firma are over and we descend to a place we don't belong, it delivers an hour or so of sustained physical and psychological terror.

On paper, the elements for suspense - sharks, rapidly depleting oxygen, a cage, risk of the bends - are all there, but on screen they add up to a whole lot of visual blah.

By the standards of cheap shark thrillers, the film is perfectly serviceable, but it's certainly no more than that.

Though the heroines make some terribly dumb moves in their bid to survive the ordeal, the script's clever reminders about deep-sea dos and don'ts will keep viewers invested in ascertaining the final outcome.

It's tense, edge-of-your-seat stuff... for a while.