Man, fk you deluge of games from xmas + bday.... *sigh*
So back to making a bullet hell in Flash, I took a look at the number of collision calcs being made. Then the "ye olde good idea fairy" had to kick in, and I thought to myself "why not have player bullets counter enemy bullets?" My desktop is pretty beefy, but even 10k calcs is proving to be pretty ridiculous.
A couple days later, I have devised a solution. The worst case scenario would be slightly worse than the default routine, but the best case scenario reduces calculations by 4x. The good news is that I have done something few would consider. The bad news is that I haven't tried it yet. The bad news is that AS3 is making me do practices that would be the opposite of what to do with better applications. The bad news is that it works poorly with large objects.
Nothing to do but to try it now. For great science!