Pretty Poison (1968)

The movie's big joke is that Sue Ann turns out to be the potent, sociopathic one; for once, Perkins is out-psychoed by an honor-roll student who worries she'll be late for hygiene class.

Like any good study in couple's psychopathology, a familiar relationship is visible here, but in a parodic, mutated form.

Once the story takes a murderous turn, things quickly fall apart. Too many perfunctory side characters, such as Dennis's clueless parole officer, dilute any sense of tension; the bargain-basement visuals-all overlit interiors and unmotivated zooms-never rise above the luridly cheap; and hoo-boy, those final scenes.