“I know I have some, sometimes, problems talking,” stammers Keith (Dore Mann), the profoundly inarticulate and emotionally challenged center of director Ronnie Bronstein’s “Frownland,” an abrasive, acute, and ultimately hypnotic examination of a group of marginalized New Yorkers. A grainy 16 mm rondo of balefully needy yet utterly stifled people struggling to personally connect, “‘Frownland’s’ sludgy miserablism,” wrote Filmmaker Magazine’s Scott Macaulay, “can be a tough watch.” Nevertheless, Mr. Macaulay and his fellow jurors at this year’s South By Southwest Film Festival acknowledged Mr. Bronstein’s “uncompromising singularity of vision” with a prize in March.

“Frownland” is, indeed, not for the faint of sensibility. The film has divided and confounded festival audiences across America. “Clean, Shaven” and “Keane” director Lodge Kerrigan chanced upon “Frownland” at a screening during the Maryland Film Festival in May.

“It was just so raw and alive,” said Mr. Kerrigan, who will introduce the film tonight at the IFC Center along with Messrs. Macaulay and Bronstein.

“It’s not an intellectual idea of what filmmaking should be,” Mr. Kerrigan said. “Instead of being derivative of other work or cut and pasted from other movies, ‘Frownland’ is the product of somebody who really has their own vision. It’s so rare to see that.”

Mr. Bronstein offers a view of a New York City populated by barely functioning people occupying cramped quarters and trying to make ends meet financially and socially in the most dulling and dubious ways. It’s the exact opposite angle from the one taken by most relationship movies set in New York, from Woody Allen’s salad years through the current “Mumblecore” vogue, in which attractive people glibly examine their lives while dwelling in huge apartments and working at dream jobs. “Frownland” takes place in a New York as scabs-and-all authentic as Celine’s Paris.

“Being in New York City and being surrounded in such a gross way by so many people all the time catalyses this desire to connect with people, to get attention,” Mr. Bronstein said. “There’s a certain kind of loneliness that makes you really struggle and grope to bond with the people around you and the community around you. But at the same time, in New York there’s also a knee-jerk repulsion. If you’re on the subway and somebody’s arm rubs against yours, it’s disgusting, it’s loathsome.” “Frownland,” the director said, emerged from “my experiences with that dialectic.”

Initially Mr. Bronstein intended to script and direct a comedy that would portray that particular brand of New York City queasy disenchantment, a sensation that many of us know intimately but is almost entirely absent from the big screen. “I played around with trying to get these very abrasive experiences I was having onto paper,” he said. But Mr. Bronstein grew leeryof”conventional scriptwriting modes and my own ability to write an absolute document. [But I] realized that I could find really interesting people that I thought fit the scope of the project and work with them doing massive amounts of rehearsal to tap into their natural speech patterns. Through their interpretation of my ideas, I would arrive at something that was fresher and had more dimensions.”

“It really started when I met this guy Dore Mann,” Mr. Bronstein said. “He was a much more severe embodiment of the kind of mental state I was in during my 20s. Dore became an extreme, expressionistic conduit for the kind of misanthropy that I was stuck in.” Their chance meeting at a family funeral (Messrs. Bronstein and Mann are distant cousins) led to a lengthy process of exploratory rehearsals, during which Mr. Bronstein sought to “strip away what personality traits of Dore’s didn’t fit the scope of the project and zero in on and magnify what did.”

Mr. Bronstein hastens to distinguish between Mr. Mann and the character of Keith, who describes himself in the film, with some accuracy, as “a troll from under the bridge.”

“I don’t want to paint Dore as Keith,” the director said. “They’re very different in their lives and Dore is a functional, charming person. He’s frighteningly bright and has so much to say, but it’s almost as if sometimes he tries to say everything that he ever wanted to say in one moment.”

While workshopping the film, Mr. Bronstein said Mr. Mann generated some “300 to 500 pages of journals he kept in character. We really dug into Keith’s history, into his childhood, and his family life.” But when working with the rest of the cast, Mr. Mann’s character “kind of turned into a neurotic monster,” Mr. Bronstein said. “When we got into rehearsals, nobody cared about his childhood, they wanted to push him away.”

“I knew that the relationships would be defined by friction and abrasion,” he continued. “But the level of vitriol that people spat at Keith was way more intense than I figured it would be and I went with that. Keith was unable to communicate and the people around him had no interest in helping him through that quandary. I really was trying to be sensitive to this off-putting character, but I felt it would be fake to make them be sensitive to him.”

In the finished film, Keith’s woefully garbled attempts at bonding with or placating those around him transform him into a sort of social martyr, a stuttering human version of the spiritual martyr characters perfected by Robert Bresson in his similarly troubling and penetrating films of the mid-1960s. Every person Keith encounters in “Frownland” exposes his or her own flaws as they recoil from Keith’s need for attention.

There’s a certain type of lightning-in-a-bottle epiphany that happens when actors fearlessly commit to the full and potentially embarrassing details of the mundane. “Frownland” packs more of those blisteringly truthful “as awkward as real life” moments into its dense 106 minutes than any dozen no-budget indies. And unlike so many of the children of Sundance, it does so without condescension or judgment, other than the characters’ own unbridled, honest, and vivid distaste for one another.

Mr. Bronstein’s film has garnered an Internet and festival reputation as a “challenging” or “difficult” work intended to confront or provoke viewers. At the Maryland Film Festival screening that Mr. Kerrigan attended, “it was a stunned audience,” Mr. Kerrigan said. “I’m sure he gets that all the time.”

While some of its promotional rhetoric pitches “Frownland” at the “I dare you to sit through it” level, the film’s extraordinary compassion is its most enduring quality. “I don’t want to make anti-humanist work,” Mr. Bronstein said. “Trapping characters like flies in jars and slowly pulling their wings off, that’s just cruelty. It’s entertainment at the expense of somebody’s dignity.”