I think I've found a bug. If you set the overall volume to 10 then start a new game, the music will be muted. Other values don't seem to cause this issue, and once you're ingame, changing it to 20 and then back to 10 seems to make the audio play again. However, once you cross to the next stage, it goes back to being muted again. I suspect something is rounding down improperly.
It would be nice to have better sound controls in general though. Playing on the browser with decent headphones, 10% volume is already plenty loud, and 20% is uncomfortably loud. It would be nice to have more gradual controls to be able to adjust the volume on the low end. If the range is not logarithmic already, I would recommend you turn it into that.
Viewing post in Hyper Bun Buster: Rocket Hammer Action (demo) comments
thanks for the bug report! i'll have to try and track this music issue down the next time i work on the web browser port of my engine's audio backend.
i've been meaning to add an exponential/logarithmic curve to the game's volume controls for a while, but i was worried it would take a lot of work. after giving it a quick try, it all worked after just a couple of minutes! so the next release will have more fine control at lower volume levels.
edit: this is fixed in v0.2.7!