I finally finished this game after (re-)starting it for more than 5 years.
Ah, it is so beautiful.
It only took me 5+ years, but it has been done and i loved it :-) .
The savegame: pers2.dat should be placed in AppData\Local\2DBoy\WorldOfGoo under the name pers2.dat.
The soundtrack can be found in Kyle Gabler’s Portfolio: World of Goo Soundtrack (original) and here (for posterity). Enjoy it!
– Some Sign Painters are more Pessimistic than others.