To transfer a save file you may need to go to your AppData. When transferring the save, make sure you also transfer your settings too otherwise it may not work.
I personally find it fascinating that you use an encrypted settings file (or at least a settings file that is not a .json as it claims to be) that verifies the authenticity of the save file through some sort of checksum, but didn't encrypt the .exe file. I wasn't quite able to figure out exactly which script does it, but I was able to see that every time the program writes to the save file it also writes to the settings file. Nifty trick to prevent save file manipulation, shame it overwrites itself on load when mismatched because I get the feeling a fair number of players are going to have just enough computer knowledge to know how to find the save file and not enough reading comprehension to know they need the settings file as well.