Beautifully shot and all the more unsettling once you know how much is taken from real life.
The choice of atmosphere over jump scare is one I applaud, but feel that by the later third of the movie there could have been a little more meat on the narrative bone. I am not saying to delve into the lamentable horror movie trope of explaining everything and removing all mystery, but just a little something.
Visually this is fantastic, and surpasses other movies that specifically try to be visual. There is a scene shot walking upstream through a river at twilight (or possibly dawn) and it is stunning.
My advice, if you watch it, is not to expect normal narrative pacing, but to just be with the movie and absorb what it is doing at any given moment.