This film was totally not what i was expecting and for this same very reason, a lot of people panned it. As an avid film fan - especially horror - i don't often find myself surprised and having no idea where this film is going, whereas watching this film I really was surprised because I expected an average run of the mill jumpy rip-off of the classics.
The ending will definitely divide viewers BUT If you want something different, seek this out. That said, I wouldn't pay more than ten pounds but it's a good little film that isn't scared to be different. A lot of people are also associating this with The Exorcist, but it has nothing to do with it and isn't a remake like I've heard one or two people misconstrue.