Is it an old save from a previous version?
Outdated saves will cause issues like that.
If you want to play the latest content for that update, you can jump to the latest content by making a new game, then jumping.
You should be able to start a new game. It's either the game files you downloaded somehow became corrupt, or something with the device you're running on is causing issues.
Delete the old/also delete the files in appdata. Then try downloading the game again on Itch or if you go to my patreon, then the about section, there's links to free version there as well, you can download