The graphics and atmosphere were amazing, if a little dark! I loved the physics of the ghost, with the billowing cloth and the slight head-turns as you were looking around. The changing of the colour/temperature of the light as it faded away was a really nice touch too.
My only critism would be that I wasn't sure if I'd reached the end of the area or just couldn't see the way through (after the long stairs up and the two jail cells). I'd love to play more of this :)