Sometimes, all a film needs is a bit of slapstick. For much of Mister John, the chances of a pratfall seem remote. And then, just when it seems that first time directors Christine Molloy and Joe Lawlor have stayed true to their inner Antonioni, Aidan Gillen pulls of a flawless tumble into a lake. It’s abrupt and hilarious, and rights a film that has seemed in danger of disappearing up its own sense of the enigmatic.

The story here is about identity. As soon as Gerry (Gillen) loses his luggage at Changi Airport, we know that he’s going to wear his dead brother’s clothes, run his bar, seduce his wife and batter the local low-life who owed him money. It’s nothing new, but done right it could be diverting. Except Molloy and Lawlor seem more interested in atmosphere and mood, as opposed to characterisation. The film looks squalid and over-heated, but all Gillen can do with Gerry’s broiling machismo is offer an occasional grimace or mildly suggestive flicker. The directors want us to believe Gerry will become his brother, but they don’t earn that possibility.

That is, until they don’t want to earn it. Only when Gillen pulls off that aquatic plunge does it become apparent that this is, in fact, a comedy. It’s a comedy about a man trying to be another man and failing miserably. Gerry is no killer. He’s slight and uncharismatic, and ultimately funks the role that we’ve movie-consciously conferred on him. Whether or not Molloy and Lawlor intended that is debatable, but the only way it can work is by casting an actor like Gillen then giving him the bare minimum to work with. And that’s exactly what they’ve done here.