Excellent!
I experienced the first 45 seconds as one big, pleasant goosebump. The dark ambient sound (ala Lustmord) felt like being trapped in an underground dungeon. The waves of distant roars and rumbles washes over your eardrums gently, each adding layer of haunting angst that will pull you deeper into the track, and deeper into the dungeon. (Listening to this with good headphones is a must.)
Needless to say ,as soon as the song faded into the piano piece, I felt a bit disappointed.
However, the ending made up for that. Those few extra pounding, rumbling basskicks left me with the same haunting feeling as before.