In Bruges

Established playwright Martin McDonagh won an Oscar for his short film Six Shooter and In Bruges marks his feature film debut. I mention his Academy accolade since this in many ways feels like two short films bolstered end to end, one a deliciously dark comedy with a heart of gold and the other a less accomplished gangster flick that is too derivative and neatly tied up for its own good.

Brendan Gleeson and Colin Farrell are Ken and Ray - hitmen, sent by their boss Harry to lie low in Bruges after Ray botches a job. Ken, older, wiser and with a much greater love of architecture soon falls in love with the Belgian cobbled streets, while Ray has other ideas - "If I grew up on a farm, and if I was retarded, Bruges might impress me." Ray is badly shaken by the mistake he made to the point of contemplating suicide, trapped between snapping at people like a disgruntled terrier and moping about like a bassethound.

The pair are waiting for Harry to call and bring them out of seclusion, but when the phone finally rings, the message he has will change their relationship forever.

The script flies along, running over with rich humour - although the language won't be to your Auntie Ethel's taste. McDonagh carefully draws the characters of Ken and Ray and Gleeson and Farrell wear them like a second skin, with Farrell, in particular, putting in a finely nuanced showing.

There's some great subplotting in the early part of the film, too, particularly Ray's fixation with a dwarf (Jordan Prentice) shooting a film in the city, and his growing relationship with local lass Chloe (Clemence Poesy), who may not be all she first appears. And McDonagh isn't scared to play to his Irish and British audience, with plenty of the humour relying on a knowledge of what makes our islands tick - including a lovely comparison between purgatory and Tottenham, which left most of the Americans at the Sundance screening looking slightly quizzical, as the scattering of us from the other side of the Pond laughed like drains.

Words including "genuinely funny", "clever" and "four stars" begin to flit through a critic's brain. You even begin to get the urge to overlook the annoying scoring by Carter Burrell, which rather than aiding and abetting the action, is more akin to a small child jumping up and down and screaming "Don't look at the actors, listen to me!"

And then it happens. Ralph Fiennes' Harry appears.

Now, I have nothing against Mr F, he has put in many a good performance but his Cockney gangsta - channelling Michael Caine by way of Ben Kingsley - simply fails to convince. This is probably more down to how well known he and his usually melifluous tones are, rather than any specific acting gaffes, but it is problematic. The character also lacks the depth given to Ken and Ray, leaving him feeling like little more than a caricature, present simply to move the plot along. It is as if McDonagh had a wonderful idea for a 30-45 minute film but, when he realised it wasn't going to quite make the distance, over-stuffed it with additional ideas just to make the feature runtime.

There is no doubt that McDonagh has an eye for the bigger picture and writes equally well for the screen as for the stage, embracing the freedom that the less restrictive medium offers, but things slot in to their designated holes so neatly, the latter part of the film retains a stagey air, that no amount of decent framing can shake. It is around this time that Burrell achieves a fever pitch of orchestration and unecessary rock posturings as the film reaches a satisfactory if rather telegraphed climax.

In Bruges is by no means a bad film. It certainly has its moments, both poignant and funny but it is precisely because its first 45 minutes is so accomplished, that the last 45 or so pale in comparison. But if, in future, McDonagh chooses to keep his focus on cleverly drawn characters and smart scripting, rather than throwing the kitchen sink at the plot, he is likely to become a big-screen force to be reckoned with.