It’s pretty clear from the opening scenes of Bullet Train that it's primary aim is to be fun. Like its duty-bound main character, it does competently enough at this - when it keeps its eye on the prize. The rest of the time… not so much.

The plot revolves around a former assassin called Ladybug (Brad Pitt), who, after undergoing rigorous anger management training, no longer wishes to accept violent jobs. After another hitman is made unavailable, Ladybug’s handler (Sandra Bullock, heard via earpiece) assigns him a straightforward, gore-free mission: retrieve a suitcase full of cash from a bullet train.

So far, so good. But the train turns out to be full of killers - some professional, some recreational, all with their own motives, and hijinks quickly ensue.

The saving grace of Bullet Train is the performances on display. Across the board, the actors are well-cast and committed. A hitman duo consisting of brothers Tangerine (Aaron Taylor Johnson) and Lemon (Bryan Tyree Henry) have excellent chemistry and could’ve carried off the movie on their own. Joey King, already a Hollywood veteran at 23, gives her all to an implausible ‘deadly schoolgirl’ role. Logan Lerman is oddly convincing as the spoiled, depressed son of a terrifying gangster.

Bullet Train is an ensemble film that scans as if it’s the companion piece to some hugely beloved series or graphic novel. It hinges on an audience’s delight at being re-acquainted with beloved characters, and therefore more forgiving of flimsy characterizations.

While Bullet Train is based on a novel, the 2010 Japanese dark comedy/thriller Maria Beetle by Kotaru Isaka (translated and re-released as Bullet Train roughly a year before the film’s release), it makes the cynical decision to whitewash nearly the whole cast, while still using a Japanese setting and iconography to furnish its plot. The resulting film is less an adaption of the novel as a distant cousin to it. This would maybe be acceptable if the filmmaker genuinely put their own spin on the idea, but the resulting look is as superficial and generic as they come.

The caper of mad-cap shenanigans, mixing violence and dark comedy, is a tried-and-true formula, and the film clearly wants to join the likes of Snatch, Pulp Fiction, and more recent hits like Nobody, as a darkly funny dazzler. But the script, amusing in places, is not witty enough and lacks the courage of its convictions to meet this brief and the fight scenes, while serviceable, never make full use of the space or break new ground.

The film's few attempts at sincerity feel insincere, and quirky touches such as Ladybug’s endless use of self-help jargon, or Lemon’s obsession with Thomas the Tank Engine, quickly begin to grate.

The biggest issue Bullet Train has, however, is its pacing. Embarking on the journey, the viewers are not given a clear enough sense of the time frame to feel any urgency. It quickly begins to feel as if we’re viewing a first draft, wherein events and characters are being added simply to keep the plot in motion. By the time the larger connection between the characters is finally revealed, what should have been an awe-inspiring revelation is merely another tedious pit stop on the way to an inevitable destination.

For a mildly entertaining romp filled with familiar faces, Bullet Train is a fine film. Just go in prepared for some long stopovers between the thrills.