I seen this movie at a cult screening party a few years back and was completely terrified after watching. As an adult i don't get scared easily for cheesy gory films. I found myself unable to sleep and to frightened to walk around my house at night. Although i still love this film and always recommend to my friends.
shareI will agree that it is probably Argento's most frightening film.
Suspiria and Inferno are both aesthetically beautiful but I found them to be atmospheric pieces of moving art, not necessarily frightening in a traditional sense.
The kill scenes were very well done here and I always found the film to be very suspenseful in many scenes, with the entire final act plagued with an oppressive feeling of dread. The rain storm, the music, the build up of atmosphere...all of it works in the film's favor in the final third.