Well, you actually CAN hear the beats
Maybe you had some sound issues in browser or smth?
For the start prototype it looks really cool and could easily expand to a bigger game with more content(enemies, buffs, levels, interactive environment etc.).
From the point of game jam it' s not that creative on the theme, but there are ways to tweak current or add new mechanics to fix this.
Otherwise... game looks super awesome, great job!
P.S. sad that WebGL didn't get to work :(
Quite interesting twist on theme, good job!
Pretty sure it would be better if you chose a better color gamma(gets hard to watch with such gameplay. Also would be great to add some background music(if don't have time or skill, just download some free stuff ;D).
Otherwise, it's very nice idea and not bad realization for 48 hours jam!