Source Code keeps you guessing as to what kind of movie it is until you’re halfway through it, and that is just one of the things that makes it wonderful and heartbreaking.
This gimmick lets Gyllenhaal shade his performance differently throughout the film. He throws bewilderment, know-it-all snark and desperation on his face with enjoyable aplomb. His counterpoint is Dr. Rutledge, the chief scientist played by Jeffrey Wright. Wright plays Rutledge as cold but not completely unfeeling; there’s enough amorality in his performance to make you loathe him but that’s leavened by the genuine worry in his voice when he talks about lives at stake. Vera Farmiga’s Colleen Goodwin plays a crucial role in the middle of the poles represented by Stevens and Rutledge; she’s the flickering humanity inside the military science mechanism and recognises that each soldier on the battlefield is more than just an asset to be deployed.
The love story that starts to bloom between Stevens and Michelle Monaghan’s Christina Warren feels trite at first, a way to aim for a four-quadrant marketing angle to pull in more of an audience. But the tragedy of cyclical death adds a bittersweet tang to it and makes the movie’s happy ending feel less obligatory and trite. Source Code is the kind of movie that deserves to be viewed as a classic in the grand tradition of science fiction: it speaks to its moment and reverberates forward, reminding us that our ability to create scientific wonders will be thrust into situations where we won’t always want it to live.