Ok I see. What browser/OS do you have? Just tried your game and it works pretty well in Firefox/Win10, cool game btw :D
So. I'm use Google Chrome on Windows 10. I also have another browser and I have already noticed that there is a difference between them for WebGL, maybe I should try and restart the browser, clean cookies, cache and see what happens. In fact, I was surprised to find that WebGL is very unstable from platform to platform, from browser to browser, form user to user and etc., but I do not understand what this is due to (the old Flash technology seems to be more reliable). Additionally, I can check with my XBOX-controller.