Adam Cook’s review published on Letterboxd :
This is a film of many contradictions. The thriller element of the story is unrelenting, exciting and always pulls the story forward but you'll guess whodunit almost immediately. The majority of the characters are little more than crudely sketched stereotypes yet you care and root for the important ones in the story. Finally, the romantic angle is impossible to truly develop because of the constraints of the concept yet it works by becoming the heart of the film. Most of the time contradictions in film are a weakness and a flaw yet here they add greatly to the experience.
If this film had been made in the '90s it would have starred Keanu Reeves and involved considerable re-writes so the thriller aspect of the story became the sole point of the narrative. The end result would have still been engaging but significantly weaker because of it. The story needed an actor of the calibre of Jake Gyllenhaal for it to work. He has been in an awful lot of rubbish but he manages to straddle the line between action star and credible actor very well. He is the heart of the film and without his performance (arguably his best yet) the finished product could have been very different. Despite the ticking clock thriller component being the thing that will get audiences into the theatre it is the emotional journey that will keep people sitting there. The bomb plot itself is handled well, returning to the same eight minutes provides the layers and momentum needed for you to care about the plight of Colter Stevens and the girl he keeps trying to save. Yet for all the twists and turns the villain of the piece is both obvious and, more importantly, redundant to the story. The script and Duncan Jones manage some great misdirection to allow the emotional journey and romantic possibility to creep up on you rather than clumsily throw it in just so an action film has something for the ladies too. It is not so much that the character revelations will come as a surprise but that when they do come they work so well. Above all it is a character driven story masquerading as something that is plot driven.
Jones does a good job breathing life and energy into a set-up that could have been very static. The film only really contains two locations - train and source code machine - and despite being billed as an action/sci-fi film, genuine action is surprisingly absent from the screen. Yet Jones keeps things always moving forward, there is never a moment where it sags and it pleasing to see him have enough faith in his actors and script to maintain an audience's interest rather than throw visual tricks at the screen every five seconds like Tony Scott inevitably would have. Gyllenhaal is ably supported by both Farmiga (transcending her duty vs morals story function) and Monaghan who has the hardest job of all by needing to be an engaging romantic foil yet only ever existing within the same eight minutes (so no real backstory, no revelations and continually repeating the same moments yet being convincing enough that Colter could still fall in love with her). They are pretty much the only two women in the film and provide the sense of hope, humanity and compassion that Colter's character needs. The rest of the men on the other hand are there to serve the plot and nothing more. This is fine with most of the ones on the train but it is disappointing that Jeffrey Wright's character is so one-dimensional and predictable and Wright's performance only compounds this.