Source Code, like its predecessor, Duncan Jones’ debut feature, the excellent Moon, centres upon a sensitive male protagonist in existential science-fiction crisis. The new film, however, is on a far bigger scale, and none the worse for that. Jake Gyllenhaal plays a pilot who is repeatedly transported into the body of a passenger on a Chicago train which is about to be blown up by a terrorist – he has eight minutes to investigate before being returned to a mysterious military lab. Very Twilight Zone, not to mention Quantum Leap (whose star, Scott Bakula, has a poignant voice-only cameo). Thanks to an ingenious script by Ben Ripley, and excellent supporting performances from Michelle Monaghan as the ridiculously cute love interest, Vera Farmiga as Gyllenhaal’s military contact, and the (occasionally over-acting) Jeffrey Wright as the cynical boffin, it maintains its humanity whilst cleverly sending up the “ticking-clock” Hollywood screenwriting orthodoxy. Towards the end, a legendary film by Dalton Trumbo is called to mind (to say more would constitute a huge spoiler), and while the conclusion maybe adds a little too much confusing SF elaboration, it remains gripping throughout. This is commercial cinema doing what it does best: taking the viewer on a satisfying roller-coaster ride.