Things that would have made Amnesia scarier

[Culinus]

8. I can't count the number of times I expected something to jump out from inside a closet or from within a drawer or underneath a pile or otherwise innocuous rubble/furniture.

I really liked the fact that you were constantly expecting something to lash out at you and it just about never happened. It constantly kept you on your toes, and by the time you've gone numb to these things something actually happened. It was a great balance imo.

13. Deja vu moments where we enter the same room/hallway twice. This was also done in an early scene in Black Plague, and I thought it was decently confusing/disturbing. "Didn't I just see this? Did I backtrack without noticing? Wasn't I going forward?"

Things that make you doubt your own perceptions are indeed the scariest things that I know of. There is nothing more frightening then not being able to trust your own eyes / ears / mind, and that's why impossible paradoxes, things that defy the laws of gravity or just things that can not possibly happen are utterly terrifying if implanted correctly. The best way is if it's implanted in a not so obvious way so that there's not just a "The protagonist is going crazy", but more a question of or "Did I just imagine that happening?" or "Didn't there use to be five people in this picture?". You should not only doubt the protagonists perceptions, but your own as well.