A collaboration between the actor Jake Gyllenhaal and the director Duncan Jones is bound to bring with it a specific set of expectations. Gyllenhaal's unstable intensity was well suited to his breakthrough role in the mysterious Donnie Darko. Jones made his debut with Moon, a film original enough to ensure that lazy journalists need never mention that Jones's father is David Bowie. (Oops.) Donnie Darko played temporal games, while Moon raised questions about identity and consciousness. The new film Source Code does both, but it's still no more sophisticated than Avatar (which it partly resembles) in smuggling philosophical baggage into the Hollywood action movie.

Gyllenhaal plays the army helicopter pilot Colter Stevens, who wakes up on a Chicago-bound train to find that the woman seated opposite him is making goo-goo eyes at him and calling him Sean. There are two possible explanations. Either it's a case of mistaken identity or military technology has enabled Colter to be inserted into the mind of a man who perished in a bomb blast on the train and to relive repeatedly the eight minutes before the explosion until he discovers the bomber's identity, thereby preventing a catastrophic follow-up attack.

Each time he dies, Colter is spirited back to those last eight minutes to acquaint himself with his fellow passengers, all of them theoretically suspects. (A halfway adventurous film would've made Colter a suspect, too.) Though the action is confined largely to a train, this is not Murder on the Orient Express and Colter is no Hercule Poirot. When he's stumped, he roughs up his suspects, safe in the knowledge that he will never be brought to book. Sensitive types in the US military may interpret this as satire.

Pleasure in the film is restricted to whatever freshness can be brought to multiple restagings of the same sequence. There are in-jokes almost too mild to register - Scott Bakula, star of the time-travel series Quantum Leap, has a voice cameo while a mobile phone plays "The One and Only". A scene in which Colter correctly predicts trivial incidents can only suffer by comparison with Groundhog Day, the daddy of all time-loop movies. That film had a 24-hour period to toy with, so while none of the supporting characters was developed as fully as the hero, we still had access to different sides of their personalities. There is only so much that the cast of Source Code can do within their eight-minute lifespan and a knowing joke about racial profiling isn't enough to stop everyone from being reduced to a thumbnail sketch, from the harassed businessman to the Star Wars nerd.

The film proposes infinite parallel realities, but it's discouraging to think that they would be peopled entirely by ciphers.

If this is a time-travel whodunnit, then it is not without precedent: in Jacques Rivette's Celine and Julie Go Boating (1974), the title characters repeatedly journey back in time to try to avert the murder of a child. Nor is it the first to use a train journey as the catalyst for an experiment with parallel realities. Krzysztof Kieslowski did just that in 1981's Blind Chance, before the makers of Sliding Doors (1998) put a frilly bow on the idea and repackaged it as a romcom.

Where Source Code differs is in its underlying futility. Colter is warned at the outset that he can't save his fellow passengers; he can only harvest the information needed to avert the murder of thousands of Chicagoans (who, being off-screen, matter to us not a jot). The film moves on from that idea, allowing some of the characters to enjoy different fates in brighter parallel universes. Yet the visions of violence and destruction can't help but seem definitive, overruling any happier alternative outcomes. A spectacular explosion shown from multiple angles or a point-of-view shot of a man being hit by a train have an indelible impact not matched by, say, a romantic interlude in the Chicago sun.

Another downside of setting a film within multiple realities is that the consequences diminish commensurately. When the world of the movie can be rebooted like a computer, there's nothing very much at stake. Few films, for instance, can have generated so little excitement from that old standby, the ticking bomb. For all the tension it provides here, it may as well be a Black Forest gateau.