Even I noticed that web version of Godot games takes more time to load up then Unity games. Can you try out mine once. It is also made in Godot. As I don't have a Mac machine I was unable to test it. If it does not work we can try different efforts setting until it works. Hopefully it will be useful for other Godot users too.
So, I tried to play your game first in the browser, and again it didn't work. The loading bar showed and filled, then the loading circle (weird that there are two loading indicators), then I get this message:
call_indirect to a null table entry (evaluating 'Module["asm"]["Bk"].apply(null,arguments)')
I then downloaded your game and played the Mac build. That worked great. It was very fun, though it took me a minute to figure out how to get the powerups, or that they were powerups at all. It looks really good, the variety of enemies was good, and I really like the way the stars(?) moved around in the background. Nice work.
I prefer Godot over Unity as well. It's all User Preference. All Godot needs is to catch up with the seamless cross-platform thing and it will hold just fine with jams like these.
As for me, I'm still sticking to the ol' fashioned Game Framework, even if I have to acknowledge that porting it across platforms is such a headache.
AFAIK Godot has still some issues with HTML5 export when using Mono (c#).
Seems to be related only to OS devices: https://github.com/godotengine/godot/issues/3526