Ah, Fulci's masterpiece. While I agree that Don't Torture a Duckling is superior in terms of storytelling, Fulci's area of expertise is the unusual ocurrences, and this film has lots of them. Very often I find reviewings critisizing it for not making any sense, but it's pretty clear that was the intention from start; since wondering what the hell is going on is pretty much scary. That, and the make-up is top notch, easily surprassing anything made by Tom Savini.
P.S: Catriona MacColl was HOT.