Most disturbing areas/moments

[Headhanger]

I have to say that my heart was beating overtime while being chased by

Spoiler below!

the shadow after you escape from the prison.

In fact, that whole area had me completely scatter-brained, trying to keep calm so that I could think clearly but constantly bombarded with the fact that time was running out.

There is the sewer:

Spoiler below!

There was that grunt who was standing with his back to me, looking down the corridor I needed to get to. I threw a rock from one corner, hustled around to the other and crept by as its back was turned, thinking I was being so clever.

Then, as I began to open the door at the end of that corridor, I heard a grunt start roaring. I thought it must be behind the door and ran back down the corridor only to see the monstrosity running towards me.

I think it missed me by a whisker's breadth as I pelted past it, just shouting to myself run, run, run, run, run but it soon caught up with me and killed me with a single blow.

It was pretty nerve-wracking because, of course, you can hear its footsteps in the water behind you, but they're muffled by your own so you can't be sure of exactly how close it is.