Heyho, this is so cool very stylish with a great audio landscape, love it!
As a fellow Godot dev, maybe i can give you a tip: you can choose a "Variant" when exporting a HTML5 game. If you choose the "Threads", the audio will be fine (right now it has strong crackling, so it suffers a bit). Some browsers (at least firefox) will not work with it anymore, but there is always the native version to fallback - chrome works fine with threads. I wish someone had told me, i had the same issue :D