If writer-director Todd Solondz doesn’t abandon his drolly harsh assessment of human nature in “Dark Horse,” he adds a drop—small but perceptible—of sympathy, or better pity, to his usual uncompromising bleakness. The picture doesn’t merely paint a portrait of misery but adds a touch of sadness to it.

The protagonist is Abe (Jordan Gelber), a pudgy, socially awkward thirty-something man-child who lives with his parents—long-suffering real estate manager Jackie (Christopher Walken) and doting enabler Phyllis (Mia Farrow). Abe works in Jackie’s office, or rather has a job there, since it appears he spends most of his time shirking his duties and buying action figures on eBay. And though he can try to be charming, in a slinky sort of way, or at least composed, he’s given to sudden fits of rage at what he perceives as the world’s unfairness to him, concentrated in anger over the success of his estranged brother Richard (Justin Bartha), a doctor he feels was always his parents’ favorite.

There’s a glimmer of hope for Abe, though, in Miranda (Selma Blair), a gloomy young woman he meets—and chats up, clumsily—at a wedding reception. Despite his alternately pushy and needy nature, she hesitantly accepts his blundering overtures. And he persists, despite a revelation about her health that causes him some concern and an encounter with her ex-boyfriend (Aasif Mandvi) that doesn’t go well.

Meanwhile, Abe begins increasingly to suffer from hallucinations that frequently involve Jackie’s secretary Marie (Donna Murphy) and nebbishy co-worker Justin (Zachary Booth). Solondz stages these without distinguishing them from “reality,” so that the viewer shares Abe’s inability to tell what’s actually occurring and what’s a figment of his rabid imaginings. And he closes the film with a twist that one can take either as a grim joke or as a slightly generous farewell to a pathetic loser.

As to the cast, Gelber really owns the picture with his lightning switches from gruff sociability to seething fury. Apart from Blair, who brings a morose intensity to Abe’s unlikely girlfriend, the others are satisfied to play what amount to caricatures, though they carry them off dexterously enough. Though it’s not a terribly polished piece, “Dark Horse” benefits from Alex DiGerlando’s production design, which opts for the brightly-colored backdrops that Solondz favors as a contrast to the dolorous goings-on that occur in front of them. Andrij Parekh’s cinematography is homespun at times, but suits the director’s vision.

The title could be taken as indicative of the film’s chances of scoring with anyone outside Solondz’s small cadre of followers, but “Dark Horse” indicates that a grain of empathy has made its way into his usual desert of despair.