“Fingers” marks the directional debut of the screenwriter James Toback (“The Gambler”), who exhibits a fatal fascination with Jimmy’s every petulant quirk. Mr. Toback, having created a character whose intrinsic charm plus 50 cents would only barely get him onto the subway, seems incapable of putting his hero in any kind of dramatic perspective, and he is apparently unwilling to explore him in terms more intimate than those of an introductory psychology course. Jimmy’s mother was a musician and his father is a boorish gangster; his mother resents him bitterly and his father wishes he’d strangled him in his crib. No wonder the kid’s got a headache.

Many of Jimmy’s troubles revolve around sex, to which he devotes himself far too selflessly, according to his doctor (if this isn’t the only movie to show someone having his prostate examined, it ought to be). Jimmy is obsessively entangled with a strange, elusive, mysterious girl (Tisa Farrow) who is so spitefully uncommunicative that one begins wanting, in the spirit of the movie, to give her a good belt. Jimmy’s machismo—he tries to castrate a rival, thinks women are sexier without birth control—is enough to make Tarzan blush.

Mr. Toback favors a stiff, staccato, nervous style of direction that’s heavy on the hocus-pocus and low on verisimilitude or insight. Aiming for a mood of nightmarish abstraction, he borders all too often on jumpy incompetence. Although the film’s production credits are impressive—the cinematographer from “Taxi Driver,” the production designer from “Three Days of the Condor,” the costume designer for “Next Stop, Greenwich Village”—and suggest that the film ought to have a good feeling for New York, it contains moments of surprising amateurishness. The sets look uninhabitable and the sound mixing is particularly appalling: A phone in the back of a restaurant rings at top volume, and the music sounds equally scratchy whether it’s coming from a tape deck or a concert piano.