Version 2.0.4, Pre-Release 9

I made it compatible with 2.0.3 saves (game mode would get messed up). I also started saving unlocks properly, because, well, I just realized that I don't know if they were ever properly saved. They just kinda worked...
I also added a check to make sure you don't accidentally exit the world and lose your progress.
Lastly, I prevented you from loading worlds saved at higher versions, though since you sometimes can't run older versions without deleting your preferences, I don't see it being very useful. :3