Bug report.
If you play Sokoban in the Ruins 2nd it shares the save slots with Piko Quest.
There does not appear to be a way to delete the saves.
It is possible that this is also causing instability and crashes in both of the games.
Thank you for reporting it.We will investigate why the save slots for Sokoban in the Ruins 2nd and Piko Quest are shared. In a development environment, slots are not shared. If you are using a Windows environment, please check that your save data is saved in C:\Users\○○○\AppData\Roaming\Godot\app_userdata.