I don’t know how this wasn’t mentioned yet but 100% use a Webgl framework, even for 2D games. Three.js is my personal favorite. Nowadays most all browsers and devices support it and I’m sure I don’t have to touch on the magnitudes of difference in speed for rendering anything on the GPU vs the CPU?

If you plan on having any amount of medium to large numbers of things (heck I’d say any amount) you’d be doing it wrong to be using the 2D canvas API.