my laptop is new and fast, but has some issues with html5 speed (and so also C2 games)- so it's great for testing (because here you see ALL problems with your game)
C2 takes 1500MB RAM - so something is off. But it doesn't matter if you have enough RAM
Bubble Game - 30fps up to 50% CPU in Chrome (debug mode)
the game isn't well optimized
But this depends totally on which computer and browser you are testing
Like with Edge I get 50fps.
The problem here is that in debug mode a lot of stuff is watched.
So if you click the "watch" tab and only monitor some of the parameters (the eye symbol) I get 58fps and 3% CPU
Some infos about my hardware:
W10 i3-5010U, 4GB Laptop - has some major issues with HTML - but otherwise a great and fast Laptop
W10 i5-6500, 16GB, GTX960, SSD Workstation - has also some issues with HTML - otherwise perfect
W10 i5-5200U, 8GB, SSD Laptop - no issues at all - runs even HTML5 like a charm
So maybe you need a new laptop
if W10 - switch to Edge in debug or choose which parameter you like to see