Something interesting- the save file is definitely corrupt. I checked my save directory and the text in the save file that's in there is only 89 characters long, as compared to a 195.8k character backup file that's also in the directory.
I'm going to attempt a fresh install and see if something weird happened to my local copy of the game. I'll wipe the appdata folder too just in case. I'll keep the older version as-is just in case there's something useful in that appdata folder for bug-hunting, since it's suffering from the same issue.