There are a few tracks that the soundtrack that GOG offer don't have: the gameover one, the 8 bit version of the halls track (galious world), "in the jungle" track, other castle song, the boss 2 and the alert music. They can be founded on the sound directory (they are ogg files but for me it's even better, its a better format than mp3) but its better if we have them directly downloadables as the other tracks. Also, the soundtrack in humble bundle has the same problem but it's in better quality, this can be improved too.