SOMA
SOMA isn’t as frightening as Amnesia: The Dark Descent, but that metric isn’t measured on a linear scale.
Amnesia: The Bunker
I don’t know what the scariest game I’ve ever played is, but Amnesia: The Bunker is high on the list.
Hyper Light Drifter
Hyper Light Drifter does its inspirations enough justice to warrant a recommendation, but it also hosts a number of imperfections that keep it from true greatness.