Very nice game! This is the most "this feels like a completed game rather than a jam game" I've found so far.
Clearly the custom music is a very strong point of the game, since it's awesome, fits the game, it's funny, and has great quality. But the overall game has so much polish and 'juice' as well (altogether, but also every single piece seems nicely animated), and even with nice cutscenes, it's a joy to play.
I certainly a lot the details of being able to adjust the volume during the cutscenes, as well as changing the speed of the game from the pause menu, without having to exit to the main menu (this was really nice surprise).
All this shows so much attention for the detail, that you rarely find in Jams. Well done!