What was enjoyable about this movie for me was that the (HD?) camera work was clean and nicely composed, the direction and acting was entirely competent and the editing was cool too, in what I imagine was a film with a relatively modest budget. A pleasant change from average Hollywood. It was made by people with a real feeling for film. Mariah Bonner as the librarian was a bonus who definitely did not hurt the eyes. Shame she was an early victim.
The story wasn't great, though it exploited common enough fears of things that are half-seen (or were they there at all?), and move in the night (as opposed to go bump in the night). And the placebo effect is undoubtedly real, though whether it's killed anyone is questionable, I'd say, certainly in Western cultures.
I did once see a shadow person in bright daylight (or did I?). I was about three at the time, and lying in bed. The shadow of a figure ran across the wall, flowed into a shallow recess, slid behind a wardrobe, came out the other side, and vanished. It was more scary than Shadow People, and as you can tell, I haven't forgotten it. However, the good news (for anyone who's worried) is that it hasn't reappeared since, and 70+ years later I'm still here.