Okay, so, a bit more playtime here, and I have in fact discovered one other fairly major issue....
Instead of describing it, I'll just do this (click to zoom in):
That's one of the smuggling missions on Misery difficulty.
You might notice perhaps a bit of... crowding, there. Now, granted, I expect lots of horrible laser doom on this difficulty, but this is... well, the issue here is that it's enough to start to cause slowdown. And if it's causing slowdown on my machine, it's going to be alot nastier for weaker ones. It's not just the bullets there, but it's also the downright silly number of ships.
This mission type is pretty crowded to begin with, but then the spawning begins, and it descends into utter chaos. There's just too many small ships flying around.
And note that this is only the part of the mission zone that my screen happens to be focused on.... there's even more of this off-screen!
And even ignoring the slowdown, that many ships makes it near impossible to go after the real targets, which are the turrets and those large things in the center of the rings.
I'm going to paste all of this into Mantis as well, along with suggestions to fix it.
Also, I still dont understand how this is "smuggling"... surely SOMEONE down on the planet is bound to notice all of the shrieking laser death and explosions going on there.
On another note, I like the wall turrets. There was a moment of "what in the heck are those?!?" when they first started firing, followed by "Ohhhh.... yeah.... those were my idea, werent they....". But they indeed do pretty much what I thought they would.
EDIT: Mantis entry here
http://www.arcengames.com/mantisbt/view.php?id=14013