Starring John Gallagher Jr. Rated 18A

The Belko Experiment looks great on paper if you're a devotee of scary movies. It's directed by Aussie Greg McLean, who blew horror fans away with his Outback-set psycho-killer debut Wolf Creek back in 2005. And it's written by James Gunn, who worked wonders helming the comically gory Slither in 2006 before hitting it big with the family-friendly Guardians of the Galaxy flicks.

Then there's the cast, which includes such genre faves as Michael Rooker (Henry: Portrait of a Serial Killer), John C. McGinley (Intensity), and Gregg Henry (Body Double).

But what looks so promising on paper doesn't always translate to the big screen.

Not that The Belko Experiment is all bad. The first half-hour is totally decent, as it tracks a diverse group of white-collar workers, mostly American, converging on their high-rise corporate building in Bogota, Colombia. McLean's keen eye keeps you involved while following office manager Mike (John Gallagher Jr.) on his commute through the colourful bustle of Bogota, the trip highlighted by a jolting jump-scare when a grimy street-merchant suddenly appears at his car window, flogging a freaky corn-cob idol.

Once the 80 employees of the recruiting firm Belko Industries get settled in for their shift, though, an unknown voice comes over the hijacked intercom, warning that if the workers don't murder three of their own in the next 30 minutes many more of them will die. Metal shutters power up over every door and window, snuffing out any thought of escape.

When the order isn't followed, a sniper starts delivering fatal headshots to random workers. That's what it looks like, anyway, but it's actually the victims' skulls exploding from the inside out. Ya see, they all agreed to have tracking devices implanted in their noggins in case they got kidnapped. They got little bombs instead.

The rest of the film is a monotonous cavalcade of exploding heads, interspersed with shootings, stabbings, and blunt-force trauma to mix things up. At one point a guy gets his head ironically bashed to bits with a large stapler.

All the numbing bloodshed is carried out for a reason, it turns out, but unless you’re thoroughly entertained by the sight of folks dying gruesomely every six seconds or so, the underlying commentary will hardly seem worth the brain-splattering tedium.