Great concept. You're right about what isn't seen is the most scary for sure. I think I've seen every zombie / splatter movie there is in my youth and I don't find them scary. The Silent Hill games and Jacob's Ladder on the other hand is perhaps the most psychologically demanding pieces of work I've ever experienced.
Cherub faced children with no facial expression or wearing sick masks is really disturbing to me coz it looks so wrong hehe.

Can highly recommend the Silent Hill series this time of year. Rain and wind whippin the windows, turn down the lights, crank up the volume, and have a spare pair of pants nearby.