They don't change the frame rate at all on my computer. Each critter adds a few hundred triangles I guess... I won't know if there is a slow down until people try it out on their computers.
I hadn't put any plans for optimization in at any specific point in the Plan, but I could try a few things for that release.
Did you put the OpenGL libraries in your project? If you don't put the OpenGL libraries in, none of the functions in the header are defined and you'll get a bunch of link errors. For Windows, the libraries are opengl32.lib, glu32.lib, and glaux.lib.
What type of errors are you getting? I must have had about every error you can get while I was trying to put OpenGL in my project, so I can probably help
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My little pyramid people can now hold any stance I choose to give them. There's one stance (on both upper legs and both upper arms) where the lower body gets reflected (so the tail is coming out of the belly and the right and left legs exchange position), but that's a minor error I should be able to catch. The function I've written should be general enough to handle any stance for any creature body -- no function can do this perfectly (some stances and bodies are very weird), but I think it is currently a good approximation.
My next goal is to get them walking around and slapping each other. Then I'll improve on the pyramid look a bit. After that it's liquid display and the other changes I'm going to make for this version.