So Amnesia: The Dark Descent received an update today that adds a new story mode called Justine which gives you a whole new story to play through. I've played through it for a bit and it's pretty neat, especially since there is a "Glados" character that communicates with you via phonograph recordings, not to mention that the monsters get custom sounds (And what appears to be a reskin) just for this new story.
Please keep any comments about the specifics in spoilers if you think it will ruin the experience for others.
Spoiler Alert, click show to read: