there are tons of soundtracks already made that were never used... I talked to Stefan about it, he says he chose not to add them because it would take up too much storage space.
Apparently iOS devices don't support MIDI files, so you have to use mp3.
I really would like it if they had an optional soundtrack extension that you could download in game, that would enrich the game even more. besides, the ~50-100 mb that would be taken up is nothing compared to the 500+ mb of graphics you get stored.
Can anyone with folder rights confirm how much storage space is used in graphics alone?