Hello Crealdew.
It would be very helpful if you could tell me the moment the game crashed exactly so that I can see if there problem is in-game or if it is some random crashing like Rpg maker likes so much.
As it seems the save file got corrupted, which is pretty surprising as a casual game crash doesn't usually corrupt a save file. I don't have one that takes place during day 2 on me but I'll be asking to some friends if they have one, hopefully I'll be able to send it back to you.
To play the game in ful screen you need to press alt+enter.
Sorry for the inconvenience, I hope to fix this asap for you to enjoy the rest of the game!