Despite all the optimizations I already mentioned I needed MORE optimizations!

The AI ships don't need to perform a front scan every frame.  So I have two AI modes - "low power" and "high power" and the ships alternate between those every frame with only one ship in high power mode and the other in low power mode.  A ship must be in high power mode to perform the following tasks - a front scan, missile scan and missile dodge initiation, changing to a new state (attack vs meander).  At this point I had cut the processing down to bare essentials without degrading functionality.  STILL not good enough!  As I already mentioned my game was way out of NTSC spec by using 286 lines to accommodate all that AI processing and wouldn't run on one of my TVs!  Occasionally I was way over processing time... in that case I would freeze the other ship in place for one frame.  This was barely noticeable and it allowed me to chop the number of scanlines I needed down to 276.  This is still much higher than the standard NTSC 262 lines.  It's ok to be somewhat out of spec and still work on most TVs.

I did a LOT of optimizing and I still just barely squeaked through!  That's what happens when you add advanced features that the 2600 was never designed for.  With Atari it's not all about how smart you are.  It's about how much punishment you can take and keep coming back for more!