Thanks for the update and all your patience! We're sad about the issue and we'll keep an eye out to see if we hear about any more clues for what might be causing it. If you got the game on its own (i.e. not in one of the huge charity bundles), feel free to request a refund by contacting Itch support and letting them know we couldn't solve your issue: https://itch.io/docs/legal/terms#refunds
Good news! I got a new computer, came back to this game, installed the new “standalone” version, and voila, it runs perfectly! I was able to finally complete the game and get one ending.
I know there’s several others, but I’m scratching my head on how to get them. I looked at the developer notes, but it didn’t give me much more to work with.