Downloaded 0.3.1 today, played it and it seems exactly the same as 0.3? Or at least I ended at the exact same place (lost save so I had to play from scratch again :/).
It is the same as 0.3.0, it's only a minor version change so it only includes bug fixes. No content has changed in this version, sorry for the misunderstanding.
Also to carry over saves you just need to copy the "state" folder from the older folder to the new one.
