It can be got to work in Firefox but you have to edit the preferences to enable canvas.transferControlToOffscreen.
This is because the 3D rendering runs in its own thread (as does the fluid dynamics based pathfinding). Firefox doesn’t support this rendering technique by default which forces you to render 3D on the main thread.
Firefox also has terrible 3D performance - it’s actually my browser of choice; but not for playing 3D games. For that Chrome runs web_gl content at about 3-5 times higher fps.