I think we understood the problem. Itch.io on the gamejam game page adds three dots at the end of the link automatically due to size. If you copy the entire link and delete the dots, you can see GDD is accesible! It's a bug of itch.io, not our mistake. Reconsider your decision, please.
Even here you can see it. Delete three dots and the link will work: https://docs.google.com/document/d/1a1msFI2ZtbUAQ2xwAmggCZYo-lN7AR04Z-Kx1B63-Fw/...