But we are testing pretty much C2 on browser.
That is expressly what we are testing, yes. Read Isn't that really enough, for now?
On launch, C2 didn't include an image editor, a physics engine, tilemapping, social media integration, complex collision polygons, multiplayer, not even half the exporters or publishing plugins, web-font support, lighting, positioned audio, LOS, debugger or profiler... the list goes on. I know a lot of these things are missing from C3 at present - but this team is no slouch! Have a little faith.