Apologies for the delay, did you use the link or download the zip?
If it's a problem with the link, I'd appreciate it if you let us know in what way is not working. Page not found error, multiplayer not connecting, sharing link not generating, etc?
If it's a problem with the zip, it will not work due to how GameMaker implements multiplayer. The zip is there to show our code and the link is for the gameplay itself. I will make that more clear in our documentation.