It looks like a new version of the demo was published along with the new chapter update. If you're using the Itch.io client, you probably chose the wrong update to install.
You should uninstall and re-download the full 'Chapters 1-4' version.
Beta2 is just the public/open beta of the newest chapter, since we're still making some minor improvements and tweaks to v0.4... which will be shared here instead the moment it's done.
That said, it's more or less the completed/perfected version, free of bugs, and save-file friendly.
