Xavier Gem certainly doesn’t waste any time. Well, not in his first five minutes, anyway. In the opening shot of The Divide we’re faced with a brisk, face-collapsing catastrophe; a vaguely terrorist-flavoured nuclear attack that takes out a New York apartment building, as well as all the tenants within. People cry, the old folk get left behind, the explodey things explode and by the time the dust clears we find ourselves in the dark basement, with – we presume – the only survivors of the blast. A few suspiciously stacked blokes, a young couple, a mother and daughter, a black guy you assume will die fairly soon and the apartment manager – the one who had the foresight to build this basement shelter to begin with. He smokes a massive cigar, so you know no-one should mess with him.

After some fairly cringe-worthy exposition and a bit of badly-heaved “DAMMIT WE HAVE TO DAMMIT WE HAVE TO TRY TO”, everyone calms down a bit and settles into the rather unhappy but much more interesting prospect; figuring out whether they should be hoping for contact from the outside world, or dreading it. It doesn’t take long for their questions to be answered; an attack by faceless Hazmat men, a kidnapping and the first of many, many deaths means that their fates – as well as the doors – are swiftly sealed. The remaining few better get used to living in darkness, counting ever-depleting supplies and trying to ignore the ragged nihilism dripping from every exchange. A hierarchy is established, rules are put in place, and life for all is flattened into an endless cycle of eating, drinking, sleeping, watching your hair fall out and trying not to get in anyone’s else’s way. But it doesn’t take very long for those suspiciously stacked blokes I mentioned earlier to realise that if need be, their strength means they rule the roost. And they aren’t about to let a little thing like morality get in the way of satiating their every, increasingly primitive desire…

Though it takes a little longer than is entirely necessary, The Divide finally gets its teeth into its central conceit about 40 minutes in: when you’re gradually being stripped of everything that makes you who you are, why bother with humanity? The Divide does well to juggle a genuine interest in this question with unadulterated blood-lust, meaning that as the set-pieces get increasingly grim (where would post-apocalyptic basements be without a blunt axe and a torture-ready office chair eh?) our interest in our doomed little gang never wavers. Though basically every character is painted in rather painfully broad brushstrokes, there’s no doubting the dedication of the cast, who throw themselves into their increasingly horrifying actions with gritty aplomb. Rosanna Arquette has the particularly unpleasant task of becoming the despised sex-puppet to the alpha-males, every unforgiving shot of her gradually decomposing face and blood-stained body adding to the horror of the acts she’s forced to commit.

Let’s be clear – there’s not a lot of room for nuance in The Divide. The paper-thin character outlines mean that we’re only fully engaged with our central players when some truly awful thing is going on, though fortunately truly awful things are basically going on non-stop. As power is relinquished, as loyalties shift and as resentments threaten to rip apart what little sanity remains, it’s left to a harrowing but genuinely satisfying climax to roller over character quibbles and sweep us on home. Director Xavier Gens’ love of quick-cuts and heavy – oddly poignant – scoring mean that at time you wish he’d stop trying to MTV the entire escapade and just let us settle miserably into the gathering darkness, but there’s no denying that it keeps things sharp and brutal.

Dank, dark, bleak and pretty relentless on the gore-score, The Divide certainly won’t be everyone’s idea of an engaging apocalypse. But if you’re willing to resign yourself to the worst the human condition has to offer, you could certainly do a lot worse than spend a couple of hours with Gens’ group. A couple of hours, mind. From what I’ve learnt, I’m not sure I’d recommend it on a long term basis.