Really very enjoyable and tense...

Rating: 8/10 (28 June 2016)

I've only recently watched this on a plane from the States to the UK and I think one of the reasons I'm writing this is how surprised I am to see 1 or 2 rated reviews here.
The set-up is cute - essentially making you guess (and second guess) what genre of film you're watching and the three leads are so good. John Goodman has the eye-catching 'is he or isn't he a loon' part but that only works as well as it does because of the other two.
So it's the ambiguity that makes the whole thing work (other reviews have criticised the static nature of things and 'boooring') but that's what makes it tense. It's set in a bunker - not a lot of room for running around. Plus, you don't quite know who to root for or who may have a yet to be revealed agenda. Well handled, simple and believable in a weird scenario.
The ending (last 20 minutes or so) felt a wee bit daft like it was an idea bolted on to a different screenplay. Having said that, this was 'softened' somewhat by adopting a tone of voice adopted from Carpenter's The Thing ("you gotta be f*****g kidding me...").
Sorry - genuinely surprised by the haters. Low key, tight, claustrophobic and tense. The ending could disappoint but shouldn't detract from what went before.