I actually just recently recorded two classic C64 chiptunes on these machines:

Commando High Score (by Rob Hubbard, 1985):
https://www.youtube.com/watch?v=ihjcUuGttKU

Delta (by Rob Hubbard, 1987):
https://www.youtube.com/watch?v=fBrhfdcia90

And speaking of sharps and flats, at least Delta is using a lot of both black and white keys - it's possible with some tricks smile