Found it at random, and decided to give it a watch, as the storyline picked my attention. Being a horror movie veteran, I know ratings are not trustworthy, so I tend to ignore them (I'd think that there may be at least 2 points of error in the ratings in horror movies).
It turned out to be quite a surprise. At first, it won't look like a big deal. One of the characters may come across as a little tiring and the acting may seem to be going a bit over the top. Although I did not find acting brilliant, it was good overall, and my first impressions dispelled. I believe that, rather than acting, it was the bad text written for a couple of scenes that caused me discomfort.
At any rate, the movie is quite dark and it grew on me. The disturbing dreams, which seems to interweave with reality, gradually throwing a fragile person out of balance, and the quite unusual narrative. The way the move progresses fascinated me; it's dark, disturbing, and verisimilar. The character plunges further into a path he can longer emerge from; he is no longer himself, but is a captive in his own body. The symbolism used pleased me.
The disturbing characters that sprang as the movie neared it's conclusion were fascinating. From one point, I was confused as to whether it was a dream of the characters, an other-worldly dimension, or simply a quite disturbing reality.
My sole disappointment was the writer felt he should he resort to Christian clichés to describe evil ("legion"). I wish writers were more creative in this respect. If they can't find words to describe evil, they should not use words. After all, that's one advantage of movies.