The game has credits in the "Game Information + Credits" readme file, which includes crediting that song, but it would definitely be a good idea to add an in-game credits as well. Thanks for the heads-up on the license as well. I get the feeling there are probably some copyright conflicts with other songs I yoinked for the game which are far less resolvable than that (which has a rather generous license all things considered), and replacing all the music in the game isn't an immediate priority right now (I don't have the old game files anymore so I can't quickly update the demo build either), but at the very least I will try to more properly credit my sources.