I've been seeing this film on scariest movie lists, and while it does not have the most coherent storytelling, there are a good amount of scares that make an impression. The film covers the tormenting phenomena in a Buenos Aires neighborhood which are then investigated by a police commissioner and three researchers.
Since the neighbors and investigators have their own experiences, the film does not seem to have a lead character to specifically focus on, which makes the focus frustratingly scattered. Very few explanations about the mythology are provided. Effective scares aside, the story needed something to anchor itself on.