No, older versions should not be played and can mess with your saves in some cases. Backing up your save data is advised. The save path is the same C:\Users\*YOUR NAME*\AppData\LocalLow\Impy
Oh ok, I see it now that I checked. Saves erased, but luckly the latest version has access to Gallery and luckly all still unlocked. Does older version even has the Gallery ?
The gallery was only added at the very end. Gallery unlocks in my games are designed to be interchangeable between versions, but general saves are usefully not compatible and will not let you play with the wrong version (I think that my older games may not always have that restriction, be careful).
