If you weren't watching the Twitch stream last week, go and watch this video right now. Stop what you are doing and do it!
https://www.youtube.com/watch?v=t9fWIGMPuEg&feature=autoshare
And if that end track is not somewhere in the game I will be so disappointed I might be something rash, like never watch a Twitch stream again!
It's really well done.
I loved the trailer. Can't wait to get the expansion.
It almost felt like Pike Industries was channeling Aperture Science, but in a more sinister fashion.
Figured I'd post it here as Handelabra posted an update about the Rook City release http://handelabra.com/blog/2015/3/31/visiting-rook-city
They confirm the variants that will be in the update as well DW Fixer, DW Expat, and America's Greatest Legacy.
Old Legs has arrived, game now officially broken.
The end track is indeed in the game, as the beginning of the Rook City environment music. 
Huzzah!
And it's just as awesome as it was in the video.