Perrier's Bounty (15)

Ireland has not had a glorious run at the movies recently (Leap Year, Happy Ever Afters), and the Emerald Isle's latest, Perrier's Bounty, does not go out of its way to win friends either. It is the cinematic equivalent of a beery St Patrick's Night reveller, uncouth, volatile, in your face: you're not sure whether it wants to give you a bear-hug or a beating. I found its profane comic high jinks quite entertaining, but I've no doubt that others will cross the street to avoid it.

Set in a Dublin of delinquent youths and dangerous dogs, it stars Cillian Murphy as Michael, a chancer who's finally run out of time on a debt to the city's nastiest mobster, Darren Perrier. He's just woken up from a night on the lash to find two of Perrier's thugs spitting pistachio-shells at him. In case we don't appreciate the gravity of Michael's predicament, a brooding narrative voiceover – listed in the credits simply as The Reaper – fills us in: "Like time and tide, I wait for no man". It seems that Michael's estranged dad Jim (Jim Broadbent) is on terms with this same Reaper, who has told him in a dream that when he next goes to sleep he will, er, die. Which is why Jim is desperately trying to keep himself awake, chugging Nescafé straight from the jar.

The rapid alternation between quirkiness and violence is a signature of the screenwriter Mark O'Rowe, whose 2003 comedy Intermission gave both Colin Farrell and Colm Meaney something close to their finest hours. (He also wrote the memorable and harrowing Boy A). This latest isn't very subtle in construction – it's a shaggy (attack) dog story about Michael going on the run with his lovelorn neighbour (Jodie Whittaker) and his errant dad – but O'Rowe's ear for the scabrous, lyrical jauntiness of Dublin patter can be extraordinarily funny. For instance, it's one thing to call your slavering pitbull "Achilles"; quite another to give him the epithet "the Invincible Fuck", as though it were on a par with Alexander the Great. And the dark intimations of how the story will play out are finely articulated by The Reaper, whose voice (just to warn you) sounds like that of a Famous Irish Actor: "Brutal and tragic events are brewin' up, righteous."

The longer Perrier's Bounty continues, the more ragged and jerry-built it looks. The violence is a Tarantinoid mixture of brutal and cartoonish, even while the bounty of the title barely figures in it. The same might be said of Brendan Gleeson, who's terrific in the glimpses we get but occupies scarcely 15 minutes on screen. The picture is consequently Jim Broadbent's for the taking, and he enjoys himself mightily as the death-haunted wanderer trying to make peace with his son. The director Ian Fitzgibbon whips it along with some urgency and the darkish tone of the caper is consistently maintained. In the end it doesn't add up to much, but it has the good grace not to outstay its welcome.