Salma Hayek's casting in this high concept thriller is a little bit more interesting than the movie itself. The plot (beautiful, imperiled woman trying to escape from a room) could be written on the back of a postage stamp, but Hayek's career has always veered between roles that trade on her sex appeal (After the Sunset) and characters in 'worthy' films (Frida, Ask the Dust – ironically it's the latter film in which we’ve seen her completely nude.

So every time she appears in skimpy clothes or underwear and/or – as she is here – streaked with blood and toting a submachine gun, you feel she's swung away from serious drama and back towards her hot tamale/sex kitten persona.

She plays the titular heroine, a captive call girl in the employ of a fearsome Asian gang who finds herself hemmed in and pinned down by a small army of armed thugs and even her own co-workers when a price is put on her head.

We meet Everly in a bathroom considering whether or not to slit her wrists and end her torment. Instead, she bursts out of the room and opens fire on the assembled henchmen, somehow coming out on top but making herself a marked woman in the process.

In a reversal of the 'basic to boss level' video game aesthetic, Everly is trapped in the apartment while waves of ever-more dangerous enemies come after her. First are the other hookers who work in the apartment complex, then bigger and better baddies and finally the head villain himself.

As such, most of the scenes do little to add to the essential plot, they're just nastier iterations of the same idea, especially when the enigmatic man known as The Sadist arrives, his specialty immobilising victims while he pours various poisons down their throats.

The only throughline is Everly trying to get in touch with her mother, who takes care of the infant daughter Everly's never had the chance to get to know, and deliver them out of harm's way before the bad guys realise they can hurt Everly by getting to them.

In the end it's no spoiler that she comes through, dispatching ever scarier, better skilled and more bloodthirsty adversaries and getting herself more bloodied and beat up in the process.

It's gory and nasty, looking at times like an exploitation horror movie in its depiction of violence, blood and guts, and it's that element rather than anything innovative or original in the story that keeps you watching.

That, and the possibility of seeing Salma in blood splattered skimpy clothes.