I've been studying a whole lot of "Adaptive Game Music" principles, leading up to this game jam -- and so, I'm very much interested in deconstructing the source song that I've selected into a host of looping "stems" (and crossfades and stingers and whatnot). And, yes, I think tempo changes are also completely fair game. I want to try to get the music to MATCH the gameplay as much as possible, without bastardizing the one fixed artist-provided rendition TOO TERRIBLY much. We'll see how many liberties I actually end up taking -- but I'm open to the process. And I'm hoping the artist will be tickled to see their work "serve" more purposes than just a simple background "soundtrack" wallpaper. Fingers crossed.