Play music from all planets at every planet.
Small changes concerning balance, gameplay, or graphics.
They renamed one of the Space Age tracks, which causes this startup error:
Failed to load mods: Missing sound when loading sound library: __base__/../space-age/sound/ambient/aquilo/aquilo-10/aquilo-10-a-15.ogg
Looks to have been broken due to changed music in that version.
Yep. I ended up making my own version: https://mods.factorio.com/mod/space-age-music-without-space-age
Hilariously, I made one just today https://mods.factorio.com/mod/space-age-music-everywhere
It also allows mixing your own weights per source and target planet.
I just looked on your code... the solutions are so trivial our code is almost 1:1 in some places.
I wouldn't have made it if I knew yours existed!
Haha, oh well :P