Things that would have made Amnesia scarier

[GoldenFalcon101]

If, by any chance, there was an invisible monster just slowly following you. You can hear it echoing your footsteps or gently whispering threats or whatever. And just when you get used to it, it attacks you. After a while it has to return to i dunno, being invisible or whatever, but you know that if you make one wrong move that annoys or angers it, you're dead.
That's probably a very bad idea, but it's the only one I've got c':