You're right about real horror, that's why this anime draws so much attention. And yes, it's like I said in the post: it's complicated to follow the story of this particular anime because of its unique way of telling several versions of it. However, when you put in the slightest effort to concentrate on the story, you are amazed at how it completely envelops you and you remain hooked on it until the end. It's well worth seeing, I assure you.
Thank you very much for the support.