Amazing, as expected
Another Homestuck fan popping in to tell you that your work (and the work of the contributing artists and musicans) on this flash was excellent, Hussie. You have once again proven yourself a very talented writer and artist.
Regarding music, as one of the other reviewers asked, it can be listened to and purchased from a link on the What Pumpkin store. Do a google search for "What Pumpkin" and follow the links from there; this particular song is "Cascade" from "Homestuck Vol. 8".