I was just coming here to ask about this myself. I get 58-62% of the game completed and then it resets to demo. I have to uninstall/reinstall to play again, but i have to start completely over. Very frustrating, done this 4 times now.
Absolutely love the game, just not the idea that there is no chance of completing it.
Is there a file where the progress is saved, that I can copy before have to reinstall? That would make it a bit easier.