In addition to the music you hear when you're playing the game, the downloadable soundtrack will include a second "Gentleman's Private Collection" of re-arranged and remixed tunes, each by one of a wide variety of well-known internet musicians. (Side note: Can I say that I don't love the term "Internet Musician?" I think it's useful, insofar as there's a certain type of musician that it describes, but it's still a kind of precious term. Anyway, you know what I mean.) Among them, Peter Hollins, he of that hilariously OTT Skyrim video, Tina Guo (the cellist from the Journey soundtrack) and Super Hexagon composer Chipzel, whose track you can hear here:
(Hear here? Hear, hear!)
The full album will be out in a couple of days, on April 24, which is the same day the game hits Steam and Xbox Live Arcade. You can pre-order the soundtrack here, and you'll get some of the tracks early.