Evilreaver posted:
< Any explanation is gonna get out of layperson-land after a step. Suffice it to say that the code for rendering creatures is bad to the point of disgrace. >

I don't think it's that hard to explain. When you're building a 3D engine, you want to do everything in large batches:

code:
< Setup;  A HUUUUUUUUUUUUUUUUUUUGE list of crap in the world; Finish.>
This is because setup and finish are expensive. What they've done is:

code:
< Setup; One thing; Finish.
Setup; One thing; Finish.
Setup; One thing; Finish.
Setup; One thing; Finish. >

...
So you spend a lot of unnecessary time messing with small objects, leaving your video card's umpteen bajillion processing units largely idle while the CPU is sweating pumping out one thing at a time. Add to the fact that the actual math being used is itself grossly inefficient, and you have a recipe for crap performance in a game that has roughly the same number of polygons as one TF2 gun.