Up there with one of the best horror films of the last decade.
Meticulously filmed, expertly scored, well acted, ingeniously thought-out. This time around I watched it with a group of college friends, and most everyone really liked it, and were genuinely scared by it (including my roommate :)
I love showing this horror film to others because its a great example of setting up a creepy/effective atmosphere and building off it. As well as pointing out you don't need jump scares and a lot of gore to be scary.

P.s. In my mind, it represents guilt. I think its a more interesting film through that lens.