It seems that since the download release of Shiny Days JAST USA has been busy compiling a list of known issues that affect the game. The list is available here and is compiled from several sources including their own discussion thread. Some of the most notable issues include one that affects your save files after reaching the Manami ending and random freezes/crashes.
They also provide a two temporary workarounds if you’re affected by the corrupted file after reaching the Manami ending, though one involves losing all your saves. For now it’s advised to not save after reaching that ending.
It’s most likely that they’ll try to work out a patch to fix issues where they can, and more information on that is sure to follow later. If you’re playing the game I can only advise you to keep an eye out on the list here since they’ll be updating it as we go.
