I moved some of my data structures over to linked lists today, in preparation for adding more functionality and gameplay. I was once fairly sceptical of their applicability in Flash but I've been persuaded around by the performance work I was doing a few months ago. In particular the overhead of accessing array (Vector or Array types) members is non-trivial, comparable to other function calls. I may do some performance tests to confirm this but I'm pretty sure this is an optimal solution for what I'm doing.
I've been tweaking the graphics code, in subtle ways so as not impact the performance. Not finished but the effect so far is quite nice and worth another screenshot:
Apart from that I was playing with a ConvolutionFilter over the weekend, so see if it was faster or better than what I'm now using. The result was definitely worse, both from a performance point of view and because of artefacts I was unable to eliminate, but the effect still was quite interesting if I got the values for the matrix and divisor wrong: