The gamma randomly doens't work are certian angles. It's really quite annoying.

G4 400
AGP GF2 MX 400 64mb
384mb ram

Certain Angles?
Can you post a couple screenshots, please?

I discovered some cases where certain viewing angles causes the ambient lighting to turn off on the asteroids. Perhaps that's what you are seeing?

same roid, some pos, different angles, dramatic differences.

home.attbi.com/~lil_panda/dump0002.jpg
home.attbi.com/~lil_panda/dump0003.jpg

Oh yeah, that.
That's a rendering bug on the mac.
For some reason it disables the secondary light of some objects in certain viewing angles. I need to track that down.

In the mean-time, you can turn off bumpmaps in the Video Options.