I've had my eye on this one for ages. Now that I've finally got around to reading it, I must say that it's an inspiring work of horror fiction that kept me guessing right up until the end.
Speaking of which; the inclusion of a post-credits scene means that this story technically has two endings. Each one has a very different emotional tone and yet both of them are canon. I have no idea how to feel about this, but it didn't detract from my enjoyment.
I am indeed disturbed.