The Geffen Playhouse’s revival of Frederick Knott’s classic thriller “Wait Until Dark” is a whole lotta fun.

The first act is a bit creaky, showing its age in a few places, while highlighting Alison Pill’s fine lead performance. The 1940s setting, changed from the mid-60s for this new production, appears to have freed the actress from the overly mannered tics she often exhibits on screen. I thought she seemed surprisingly at home in the period, capturing Susie’s plucky spirit without relying on self-conscious gimmicks or quirky bits of business. Aside from her role on HBO’s “In Treatment,” this might be the most natural I’ve seen her.

Mather Zickel is dependably solid as Mike, making it easy to believe that he could gain the trust of a vulnerable woman in over her head. His square-jawed charm helps sell the character as a professional con man, and as the story progresses he exhibits a welcome air of desperation. Plus, his final dive down the stairs is nicely gruesome.

Adam Stein as Roat wasn’t working for me at first, but by the exciting second act he was totally in the psychopathic groove and I appreciated what he was going for. Early on, he seemed to be channeling John Waters for some weird reason. But once the lights went out, he was a maniac to be reckoned with. His knife-wielding stage leap elicited a few genuine screams throughout the audience.

On a technical level, the apartment set felt nicely lived-in (loved the rain falling outside the windows), the lighting effects were beautiful (particularly during the climactic refrigerator gag), the sound design was subtle yet intriguing (an eerie low hum emanates whenever the tension builds) and the fight choreography was impressively brutal. In fact, during the curtain call, when the stage lights went up, I was pleased to see just how much blood was actually covering Pill’s face and dress.

“Wait Until Dark” was well worth the wait.