Hey, thanks a lot for reporting this!
Could you share what web browser you're using?
Safari on OSX. Got it working in Firefox took about 5 minutes to load though, loaded much faster in chrome (60 seconds). To be honest I've seen a bunch of issues with Godot's html build.
Glad I persisted and took the time to get this to work. The game is really good, love the mechanics, theme and music!