Hmm, this is an odd case that I don't think I've seen happen before.
1) Have you tried installing via the Itch launcher app? (https://itch.io/app)
2) Do you have any mods installed?
3) Does this also happen if you start a new game and save to a new slot, then try to load that save? If that works, then the issue might be with the save files, in which case if you share one of those files, I should be able to fix it and return it to you.
4) In the folder Didnapper 2/www/logs/ there should be a crash log file where the full error message is displayed. If you could share that, either by sharing the file, copying the latest messages in it or taking a screenshot if it, that might help shed some light on what's happening.
Sorry for the inconvenience!
I appreciate the suggestions. I am running it off my desktop so I'll try the launcher.
Well I figured it out. My main saves for the game (saves 1 and 2) somehow get corrupted. They show 0 KB compared to the other ones. Not much to do about it. I have a different save from the beginning of the epilogue so it's not a total loss but I was on chapter 5. Oh well. 