While not generally considered an example of neo-noir, the film does include certain elements of the genre, including a femme fatale, a character trapped into circumstances beyond his control, criminal protagonists and, of course, murder.
Like any good study in couple's psychopathology, a familiar relationship is visible here, but in a parodic, mutated form. In clear stages, Pretty Poison details the gradual inversion of Dennis and Sue Ann's power dynamic—a transference of roles between the apparent exploiter and deceiver and the apparently exploited and deceived. Self-possessed Sue Ann takes the driver's seat and winds up dropping Dennis off at her convenience, like a distracted mother ("Hasta luego, nut!"), while he is left stammering his story to a pair of detectives from the Kafka Agency. Locked away all those years, Dennis doesn't realize that innocence isn't what it used to be, so it's he who winds up losing what is left of his own boyish trust. The measure of the movie's cynicism: It doesn't deal in predators and prey—only in predators of different species.
Director Noel Black, in his first and only celebrated feature, has the era's typical zooms and second-long flashbacks (to Dennis's burning youthful home) in his arsenal, but utilizes his leads' strengths in making Lorenzo Semple Jr.'s dialogue, adapted from a novel by Stephen Geller, play as a cracked, baroque duet. Perkins's deadpan, stilted spy nonsense ("We're striking a blow for every decent citizen in this area") sounds like the delirious hambone speeches Semple wrote for the loopy Batman TV series, though it's Weld—who reputedly loathed her performance—at the center of the movie's indelible images of a teen queen playing at murder: straddling a corpse in the shallows of a river or taking charge of vengeance against her sneering, chain-smoking mother (Beverly Garland). "She looked surprised" is Sue Ann's spacey analysis of her senior-year rebellion's latest casualty, and Pretty Poison dodges having her taste for mayhem come off as misogyny; rather, it's the complement to her feckless boyfriend's pronouncement, "You do have quite a capacity for loving."