I truly do not understand the lower rating here. Regardless if you 'liked' the film, I think just about anyone can easily tell that it is very well done. The mood and atmosphere, which I feel is of UTMOST importance in a Folk Horror film, is done quite well and builds a nice, creepy tone. That is only enhanced by excellent cinematography and very competent writing and acting.
I wouldn't say that this movie is among the VERY best of this type. Ben Wheatley's 'IN THE EARTH' and the family produced film 'THE DEEPER YOU DIG' are superiour, especially the fantastic mood/atmosphere created in the Wheatley film. But, to me the quality in the way it was conceived and executed is certainly far above average in my lowly and wretched opinion.
If you like creepy Folk Horror, I really think that you cannot miss in watching this film. Some have thought the 2nd half of the story was somewhat 'Muddled' and unclear, but to me I felt that specifically in the 2nd half, the motivations of Mary and what and why she was doing what she was doing were very clear. Also, without any spoilers, the ending I feel is definitely showing us what MAY happen and why.
I very much enjoyed this movie and for those who like this type of Folk Horror I would indeed recommend it!