I am about half way through my js31k project and it is looking really good so far.
I got an avatar moving on my parabolic grid plan which makes for an interesting fire pattern.
I have some basic enemies that look pretty and that fire back. Collision detection working for the whole lot and the right bits dying when hit by bullets.
You have to touch somewhere on the black square to 'call' the avatar to you and then you should have a working game prototype at this link.