Well, does it kill? The answer is definitely yes, no and sometimes. In other words, success depends on what’s happening in “American Psycho,” the alternately dazzling and dull musical about Patrick Bateman, the singing/dancing/slashing ’80s investment banker/serial murderer.

From moment to moment in director Rupert Goold’s ghoulish, hyper-stylish and slick splatter musical, I found myself pummeled between affection for the witty ingenuity and annoyance with the flabby repetitions in what desperately wants to be both high-camp beefcake and an audacious Wall Street satire. It is possible, perhaps even inevitable, to be both delighted by the mean-spirited glee in this flashy adaptation of Bret Easton Ellis’ one-time scandalous 1991 novel and the 2000 movie, yet benumbed by the cardboard depictions of homophobic, misogynistic, designer-obsessed supporting characters.

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But then, in the middle is Benjamin Walker (“Bloody Bloody Andrew Jackson”), so weird and nuanced as Patrick that misgivings about the vehicle feel almost churlish. This is a wonderful performance of an awful guy. He’s a gym-chiseled master-of-the-universe trainee, spoutings the wisdoms of Donald Trump, an extremely well-dressed (and almost undressed) fellow whose insecurities and narcissism are buffed into a GQ billboard of Calvin underpants, pinstriped power suits and blood-red suspenders. With his square jaw, scrubbed skin and long bones, he looks ready-made for hotshot acceptance. But when he dances, that hard body melts into squishy rubber and you see the dorky misfit inside.

As Patrick sings, soon after emerging from a vertical suntan booth, “We look expensive, but we’re apprehensive . . . uh-oh, uh-oh.” The score by Duncan Sheik (“Spring Awakening”) is an ingratiating mix of period pastiche with smart lyrics and snatches of real time-warped hits by Prince, Tears for Fears and Huey Lewis.

Goold might have taken one of Patrick’s cleavers to a few of the more redundant scenes from Roberto Aguirre-Sacasa’s book. But I wouldn’t want to lose a swatch of Es Devlin’s ever-morphing box set with the amazing nonstop videos by Finn Ross (who did equally spectacular work for “The Curious Incident . . . ”). Katrina Lindsay’s costumes are ideally flattering and ridiculous. The least subtle element is Lynne Page’s choreography, including goose-stepping, aerobics and evocations of strike-a-pose music videos.

The men are excruciatingly buff and absurd. The women are all tough and empty, except for Jennifer Damiano as the nice girl, who is a doormat. Students of the source material may want to know that the ending has none of the ambiguity of the novel or movie. There is, however, plenty of blood.