x2.
So much to love about it, from the fantastic story ambiguity throughout to the great performances (who would have thought Neil Maskell could show this sort of depth?). I was also particularly impressed by the taut, claustrophobic direction with it's choppy, unconventional camerawork.
Whatever you do, DON'T read anything about it, just watch it. It's one of those rare modern movies that doesn't signpost every single aspect of the story and leaves you to make up your own mind.
Recommended.