One of the first films to scare me in a while!
Might be because it's late and I watched it through headphones but I was tense during the whole film!
Considering I had never heard of this film and stumbled on it by chance I was impressed.
I even liked the whole 'possession aspect' vs 'lack of oxygen' as it seemed to add to the creepy ness.
Any other films that are not well known that are like this?