Hmm, collisions would be a good idea here, specifically so you could see what was going on. Really cells are slightly transparent anyways so even with collisions it would still look nice. Also it is really jittery, but you are already doing something about that as you said.
I have an idea however, you could have collisions on and make it so the camera will zoom out as more and more cells hit the outer edges of the screen. Otherwise without collisions I keep getting this here:
And that does not look like 2048 cells haha.
You could always make an option for middle mouse button scrolling and WASD camera movement as opposed to it being fixed. Or even make it 3d, because little spheres are not hard to make in any 3d program.
Anyways just some ideas.
RIP Max-Tuesday, November 2 2007
You will be dearly missed.