Genre-busting horror movie, of the sort where it's virtually impossible to say anything about it without revealing crucial plot surprises. From the very start of the movie the audience is aware that the five hapless young things on their way to experience a weekend's bucolic romp at a remote cabin are being manipulated by a team of techies secreted in an underground bunker. What you don't know at first is why, and the suspense consists in figuring out the overwhelming importance attached to the successful slaughter of the students by (apparently) a well-funded government agency.

It's an ingenious, well-written, fast-paced, beautifully acted movie, with plenty of shock moments, lashings of gore and a teensy splash of nudity. It was originally made in 2009, just before Chris Hemsworth became famous, and thus it's impossible to predict who (if anyone) will survive to the end of the movie. The last twenty minutes are utter mayhem. Great fun and highly recommended.