SOURCE CODE (Rated PG-13 for disturbing images, some profanity, violence): It's been compared to "Groundhog Day" for its repetitious succession of events, but that's a superficial examination. It's true, our well decorated Captain Colter Stevens (Jake Gyllenhaal) from the war in Afghanistan does find himself crammed into a space capsule from which he is forced to repeat a pivotal 8-minutes of his life during which he will hope to deter the detonation of a bomb on a train to Chicago and then, later, to deter the devastation of the city itself with a dirty bomb. Find the bomb, then find the terrorist with a detonating cell phone, then prevent the catastrophe - that's what he's told by a military officer (Vera Farmiga) whom he views via a closed circuit transmission.
What he doesn't realize at first is that he's already "dead," that he has few choices to make regarding his plight, yet that he must make snap decisions on each revisit to the train, complete his mission, then return to the capsule where he will finally, gratefully, accept his demise.
One complication: as the French say, "Cherchez la femme." She's the sweet thing (Michelle Monaghan) sitting opposite him on the train, with whom he almost instantly falls in love. So now he must try to save her - and possibly himself - to live happily ever after, once the deed has been accomplished. Possible? "You can't alter the past, but you can affect the future," he is told.
The success of the film rests solidly on Gyllenhaal's performance and, lucky for us, it's strong and believable enough for us to care about him and his future. Farmiga offers a humane, sympathetic response as the person in charge of his and the city's fate. Monaghan - well, she's just a pretty, nice reason to further complicate the plot while offering a bit of romantic intrigue. The task of explaining things (to us as well as to the captain) goes to Jeffrey Wright, the apparent architect of the project.
The rest is a very clever combination of Ben Ripley's purposely (I think) complex script with its gradual development of information about a Source Code and its application to the captain's life, as information and action zoom along as rapidly as the train to the city - that, combined with Duncan Jones' tight direction (he did something as intriguing with "Moon"), seamlessly smooth camera operation, especially on a cramped, bi-level train, by Don Burgess - and a sound track with music that aids without interfering with the action - it all adds up to a thrilling, if not entirely clear or plausible, hour and a half of suspense.
Louis Morin's sci-fi special effects are perfectly conceived, used only when necessary to further the storyline - which is fine as long as one doesn't dwell too heavily on an occasionally questionable moment.
The clever conceit is that we find out what's going on simultaneously with our lead character as it's doled out to him, bit by suspenseful bit. Might not hurt to watch the movie a second time to clarify and connect all the dots, but for now, it's 93-minutes of solid entertainment, taken as sci-fi action, suspense, fantasy and romance (and even familial father/son wrap-up) in one neat package. (Grade: B+).