For some reason on chrome mobile, the keyboard doesn't show up when you try to input your username, and the game is unplayable because of that.
Oh, it seems to be a Godot web export issue. I'll find a workaround and patch it soon. Thanks for the report!
I've just released a patch (v1.2.2).I catch the Godot error and launch a native browser prompt, so you can enter your username and restore the game!