Martin McDonagh is funny and vulgar, accomplished and insecure — just like so many of his fantastical characters.

One would think that the director of a film — a debut feature, no less — chosen to open the Sundance Film Festival would regard his project as an unmitigated success. But not Mr. McDonagh, the sensational Irish playwright who returns to the stage every few years to wow audiences and chalk up one Tony nomination after another. In 1998, it was “The Beauty Queen of Leenane,” about a dark and dysfunctional relationship between a grown woman and her elderly mother; in 1999, it was “The Lonesome West,” about two brothers who can’t help but bicker after accidentally shooting their father; in 2006, it was “The Lieutenant of Inishmore,” a blood-soaked, business-as-usual tale of terrorism in rural Ireland.

Mr. McDonagh’s specialties are claustrophobia, guilt, dark humor, twist endings, and serrated dialogue. Watching an audience member walk out of one of his plays is not all that uncommon, nor are the emotional outbursts that explode from his characters, who often start the dramas rotten to the core before revealing just how many shades of gray can be found in the darkest of hearts. Many of the same ingredients are at play in “In Bruges,” Mr. McDonagh’s edgy and hilarious feature film debut, set to kick off Sundance tonight in Park City, Utah, before making its premiere on New York screens February 8.

The film’s story is a classic, contradictory slice of the McDonagh universe. Ray (a squeamish and impatient Colin Farrell) and Ken (a wise and calming Brendan Gleeson) are hoodlums and hit men, dispatched to the quaint, beautiful Belgium town of Bruges after successfully carrying out a murder, told to lay low and await further instructions. “In Bruges” opens as a sideways variation on “The Odd Couple,” with the moody Ray espousing his explicit hatred for the charming hamlet as the mild-mannered Ken encourages his friend to enjoy the respite and join him for some daily sightseeing. Next to the lovers and the American tourists, here are our felons — wide-eyed and jaded.

“I went to Bruges for a weekend on my own maybe four years ago,” Mr. McDonagh said recently. “I went to the museums and played tourist, and part of me was enjoying it so much, just amazed at this little place that had never been in a film before. But then I had two days there all alone, and you can kind of walk around the whole place in two hours, and there’s not an awful lot of nightlife, and I just started getting bored and irritated and pissed off. And I just wanted to go and get drunk. So I think this story is a way of letting those two characters in my mind talk to each other — the cynical guy who’s sick of it all and the one excited about taking in the ‘culture.'”

Indeed, these two accidental tourists bicker and banter relentlessly, avoiding any serious discussion of their grim profession and all but ignoring a tragedy that only later comes into focus. For an experienced playwright, such a complicated juggling act of funny and frightening would be another day at the office, but of course, it’s never quite so easy for a playwright trying to direct his first full-length movie — especially one who has never even directed a play.

“There’s something very different between a play script and a film script,” he said.
“You know you’ve got a good thing on the page with a play, but there’s a different leap you need to take with a film script. There’s so much going on, you don’t really know until the very end what you have.”

It’s for these reasons that, even now, Mr. McDonagh isn’t entirely sure how “In Bruges” will be received. And if one is to take him at his word, he also doesn’t much care. Calling attention to the fact that he has never worked as a director in the theater world, relying instead on others to translate his prose for the stage, Mr. McDonagh regards “In Bruges” as a new medium he has yet to master.

“The intention was just to do one movie, to have one work that I was proud of,” he said, noting that the experience of filming “In Bruges” was much more positive than he had expected, enough that he may be tempted to do it again — depending on how it plays with movie audiences.

Of course, the 37-year-old London native has found success as a filmmaker once before, in the form of a 27-minute short film called “Six Shooter,” about an unlikely meeting aboard a train between an older man mourning the death of his wife and a bizarre, psychotic youngster. Despite the Academy Award it earned him in 2006, Mr. McDonagh expressed frustration over the film’s lack of visual flair.

“I didn’t think visually enough,” he said, detailing the ways the production of “In Bruges” balanced his theatrical concerns for his actors (the first three weeks of the seven-week shoot consisted of in-depth rehearsals with Messrs. Ferrell and Gleeson) with a more thorough cinematic process of storyboarding the film’s look and feel. Yet despite the success of the shoot, and the pride with which he discusses the talent of his cast and crew, Mr. McDonagh seems to be holding his expectations at bay, insisting that he’ll be content if this is the only feature film he ever makes.

He said he’s already planning a return to the stage, drafting the script this year for his first play to be set in America. And he adamantly maintains that regardless of how mainstreams audiences react to “In Bruges,” there are a handful of moments he deems perfect — scenes that have made the adventure worthwhile.

“My favorite is probably the scene that takes place at the art gallery — which is a real gallery I might add — where Ray’s walking around and seeing these horrific, bloody paintings,” the director said. “It’s such a contrast, the antithesis to selling Bruges as this tourist destination. And then there’s the scene on the bridge, where Brendan and Colin talk about heaven and hell, and then go on to talk about hitting that guy at the restaurant in the face with a bottle — that’s the kind of moment I always go for, something that’s really funny but in just two lines it becomes really sad and kind of distressing in a way.

“Oh, and then there’s the scene where they karate chop the midget. Brilliant.”

ssnyder@nysun.com