On one of my phones, Nokia 1020 canvas2d working even faster than webgl, and here no webgl things yet, so problem is in collisions, map size etc. I know, smaller map can help, but it can't be smaller. I have statics in different frames, for example walls are one object with 20 or little more frames.
This is only test, I am not sure yet I will stay on C2, means js/html5 with my project or I need to move to other faster "engine". I still have a hope, I can do it in C2, because work is much faste than in other engines and in theory, I can do everything I need in this game. I need only stable fps. With few enemies on screen and some effects fps is still acceptable, I'm doing more tests now