So can you devs please explain your soundtrack to me? You claim it's "50% original" but list a lot of classical music tracks (Habanera from Carmen, Chopin, Mozart, etc.)

While these compositions are all public domain, the performances of them are not. They are the property of the performers. If you guys performed the music that's fine but from what I've heard unless you somehow have an orchestra hidden in your studio, you can't just use performances of the piece in your own work.

If the performance is public domain then that's okay too, but most are not. Just because the music is public domain does not give you to right to pull the music from YouTube or wherever. Music like this must be licensed unless you're performing it yourself.