Maybe you didn't see it as a child - Regan's decomposing face, yellow eyes and jolting bursts of speaking in a man's voice are all terribly chilling.
Rock music in Italian horror!
Argento at least has the balls (probably against all production advice) to hit us with some of the heavy stuff when we least expect it - poor dead Donald Pleasance carried away to blasting Motorhead in
Phenomena? Top stuff.