"At any rate, it's notoriously hard to define a giallo. It's not a formula quite as much as a mood and a point of view, and if The Girl Who Knew Too Much is a bit breezier than many of its children, it still shares their casual acceptance of metaphysics as a component of medical science, cops who'll believe anything but the hero's eye-witness account, people doing everything they can to find a killer, and are then shocked when they run across the killer. In the next few weeks, I hope to dig up some of these trends when I can find them: in the meanwhile, let me conclude by proposing that The Girl Who Knew Too Much is a gialli like The Texas Chainsaw Massacre is a slasher: it created the genre, and the rules followed, and thus it's hardly the germinating film's fault if it occasionally ignores those rules." - Tim Brayton, Antagony & Ecstasy