the audio re-mixes are the 3rd choice on the main menu, first is the video, then the dual commentary, then the re-mix. the parabola one is about 10 mins (it's only the re-mix of parabol though) and the schism one is about 20 mins
I thought the remix was pretty good, really really ambient..I watched it with my dad, bro and sis...they all had their eyes closed but I just sat there looking at the screen. It's kind've uneventful and at 11 minutes long or so, it gets tedious to listen to.