In director Duncan Jones' second film (the first was Moon), Jake Gyllenhall plays a man who suddenly finds himself in another man's body with eight minutes to discover the identity of a bomber on a train. Each time he fails he is given another eight minutes. Basically, Groundhog Day meets Unstoppable, and it's pretty great. I liked it more than the more cerebral Moon; in some ways, despite its high concept and questionable quantum physics, it's a very basic film, low on twists, and more intent on ratcheting up the tension and finding the emotional heart of the story. It does go off the rails (in many ways) in the final third becoming, for me anyway, too much of a heart-string-puller, but it's a minor complaint. Eighty minutes well spent out of a possible ninety. Think of it that way.