Heya, sorry for the delay on the response on this. I did some research and unfortunately, I'm not sure if I can fix the issue you're having. The old demo was made in Unity while the new demos will be made with the Godot engine.
If you have the time, can you take a look at my game Neko Touch? It's on my itch.io page. It has a web build, and I want to see if you can run that one. Renapet will eventually have a web build, so that might be a good work around for the future for you.