It's because you're using an older save files.Try re-downloading super latest version (I tried modifying some codes to make it hopefully compatible with old save files)
But I did check for updates and there were none
When did you last download it? Latest version should also enable you to replay endings from ending list screen (the only visible change).
Today I went into itchio and clicked on the link to check for updates and it said it was up to date unless I need to start a whole new game....
