Utterly fantastic work. Definitely enjoying it so far. That being said: I'm playing through the itch.io client, and whenever I try to save, I get this error. Oddly, autosave seems to work fine, though.
oof unfortunately i have no idea how to fix this. i'm far from a coding master but hopefully autosaves work for you for now! have you tried playing on a browser instead? i find that has way less problems <3