I will be blunt.
If you want near perfection on desktop and mobile, Flash is your solution. It works consistently on all mobile devices. It lets you do sounds, visual effects, and more without worry. It is high performance (compared to HTML5), and it has been for many years now.
It simply works.
HTML5 is still very, very new, and your results will be inconsistent at best. Your experiences are normal, and don't expect it to get any better soon.
See the biggest problem with HTML5 is it relies on technology companies working together. LOL! LOL! Sorry, but I couldn't complete the last sentence without laughing. Let me continue.
If you want to develop HTML5 games with the minimum of fuss, HTML5 isn't yet the way to go. Stick with Flash, and experiment with smaller HTML5 games on the side until the technology fully matures.
P.S. Your game sounds wonderful and refreshing. We need more artists like you making games. Don't give up, OK?
Steve