That Source Code doesn't entirely succeed as a thriller isn't necessarily a weakness. The film is structured around repeating passes at a fixed scenario. Captain Colter Stevens muddles through a confused sequence of events in search of a perfect playthrough. This event repetition also allows the film to explore varying degrees of success, from getting lost pursuing a red herring, to stumbling at the last hurdle. In Source Code, a scrappy action conclusion isn't quite enough for the player. He wants a replay so he can iron out his mistakes, construct a future for his playground, and account for his own personal dilemmas. Source Code is a video game. Stevens wants to beat his high score. He wants the good ending.
