I took a bit of a break this week for the bank holiday, but otherwise have kept working on the game. The front end is in, though not working, and I've been adding code to handle starting and restarting the game without it falling over or running out of memory.
Mostly though I've been working on graphics, trying to fix a glitch in the way the gradient shaded circles are drawn. This was a subtle glitch in game but rather more obvious in the front end so it was time to fix it.
I tried creating two new shaders for it but that didn't work as expected, because of some oddity in how Pixel Bender shaders handle alpha in Flash. So I decided used a different approach relying on an existing shader and some BitmapData API calls, especially copyPixels.
It was a subtle glitch, probably only visible to me as I knew it was there, but it's now hopefully fixed. The rendering code becomes a little more complex but it's not code that runs every frame or few frames; at most it runs a few times a game.