Hi, you need to fix the issue on the fullscreen. I had this same issue in my game during publish, and ended up choosing massive screen sizes to fix these errors. What you should do is
1. disable the "Enable fullscreen option" given by itchio. This doesn't fix the issue and makes the problem worse, so disable it.
2.Instead, for the game size, choose custom and give bigger dimensions to a size where you can see the blue icon which is a different fullscreen button given by unity to enable actual fullscreen. (If you're hesitant in given custom sizes, enable "Scroll bars" setting given by itchio.
3.Try now. I had same issues as the others, not being able to play the game at all. Its a shame all that work is going to waste just because of a browser issue. Good luck!