warning: this process will delete all workshop levels and saved settings on your guest account. back up anything important.

to be able to play the campaign again from the beginning, you'll have to make use of the guest account. in windows' search bar, look for %appdata%, there navigate to Local\PlatformerBuilder\UserData\Guest. there you should find a file named save_data. delete this file and boot up the game. log out of rumpus into the guest account if you haven't already.