I found this while browsing for some graphics update for outcast while I was downloading the game.
Anyone tried this already
http://lemonshare.net/PC-Games/3451.html

I´ve seen it too, but I don´t give it much credibility. In readme.txt it states that after instalation you can choose 400x300 and 512x384 resolutions - which are already there, anyway. Moreover, the files are about the same size, so textures can´t be much better.
I didn´t bother to risk problems, I stay with good ol´ OUTCAST.

Well, I gave it a shot.
My conclusion= Don't bother..it improved nothing.

http://www.gog.com/en/forum/outcast/a_new_640x480_fullscreen_patch_version_4_dof_fixed