This movie is so underrated! If you've actually lived with and experienced a loved one with Alzheimer's disease, Parkinson's w/ dementia, sundowner's etc. then you know strange things happen to persons with those illnesses. I've experienced scary situations irl with a relative with this (like almost being ambushed with a frying pan in a pitch dark house at night). This movie takes a devastating and sometimes very scary illness and adds the fiction of jump scares, mystery, uncertainty, and horror. Those things added to the already naturally terrifying illness itself and its progression makes for a very interesting and compelling horror movie. It's not for every horror movie junkie loving blood, guts, gore, and raunchiness. Instead, it plays on real terror of something we could all actually experience with added supernatural events though of course. The possibility of any of it happening irl is what truly can lead to a great horror/suspense movie! Just my opinion!