If anyone can’t access the link and sees this error message instead:
It’s because, for some reason, the URL format has changed for all games.
It used to be:
https:// cogdemos.ink/play/author/game-title
But now it’s:
https:// cogdemos.ink/play/author/game-title/mygame
Edit: @EvilChani Is this a bug or a permanent change?