As the lights dim in the theater, choir music swells between car horns and subway brakes.

Suddenly, David Berryman, a Pulitzer Prize-winning Broadway playwright, hurls epithets and insults in a blind rage against the state of the theater from his dated Upper West Side apartment. As her father rants about his rise to fame, Ella listens with growing insecurity that she’ll never win his approval and become a star.

In Halley Feiffer’s “I’m Gonna Pray for You So Hard,” presented by The REP, bitterness is the constant flavor. For the first 30 minutes, David engages in a vicious and frequently offensive rant, detailing his Russian father’s disapproval of a profession in the arts, his abandonment of his family, the tragedy surrounding his sister, his mentorship from a famous playwright and his present as a renowned dramatist. Meanwhile, Ella listens with mock enthusiasm and a bit of understandable dread as David lashes out on everyone from directors casting vapid ingénues to even Arthur Miller.

The tension becomes clear when David resolves to read the review of Ella’s debut show, for which she was given a supporting part while her rival Clementine received top billing. When Ella’s name only appears in parentheses, the vile wine-fueled reminiscence between father and daughter grows into a complicated battle for pride and respect, vacillating from adoration to disgust to despair. The vices go from bad to worse as David’s twisted tutelage coalesces into one line: “Be anything but safe.”

After sitting through the often unhinged first act—90 minutes plumbing themes of addiction, mental illness, incest and artistic ascendancy at the cost of family suffering—too late does the payoff emerge in the second, a mere half hour, as the Berryman’s relationship is probed five years later. In addition to the uneven structure, shifts in tone seemed glaring. David’s absurd tirades generated uncomfortable laughter, and then strains of dramatic music during tense moments practically shouted to the audience, “You should be anxious now!”

Furthermore, tunes from “West Side Story,” sung throughout the play, distract from the plot. They seem included only to underscore David’s already obvious psychoses and milk easy emotion from the audience.

As David, Martin Giles believably navigates the shades between caustic venting, drug-addled advice and mental breakdown. In this role, Giles receives the lion’s share of the lines and exposition, giving him plenty of room to chew scenery to intense effect. Cathryn Dylan, as Ella, has to watch how often she chooses to fake laugh in the opening scenes. However, Dylan makes the most of her moments to shine as her character grows from passive reactor to serious parallel of her father’s vanity. Both offer disturbing (yet effective) transformations later on in the show, further reinforcing the all-too-brief second act.

Like the title suggests, “I’m Gonna Pray” does have a spiritual side (the choir music notwithstanding). Feiffer cuts to the bone about a theatrical life and the consequences of ambition to bring even the most irredeemable characters to their knees. If only enduring such long, fraught discussions had led to a wholly satisfying resolution.