To start, watch it in Italian, I'm sorry but America just ruins everything it touches, including dubbing.
Will say, it's not a perfect movie, not at all, but it's one of my favourite horror movies.
I saw a review saying it's about bending your knee to conservatism or something, and I find that dumb. This movie is clearly about overcoming fear. The gory scenes have a power creep. First scene is mostly showing reactions to it, rather than watching the gore. The next few times you see more and more, until the last gory scenes where we see everything in close detail. As the main character is overcoming her fear, we are overcoming our fear of the gore.
Warning: next bit is a spoiler:
You have been warned
The fact that the victim is able to make the bad guy feel like such a wimp is super powerful. She is doing what he has been doing to his victims, and he becomes afraid of what he is doing unto others.