One of my favorite features of the Unreal/UT engine was the GUI based advanced options menu invoked via the console. You could hand edit a lot of these settings by editing *.ini files or via the console, etc. but having all the "nuts and bolts" of the engine coherently organized in a GUI menu was a really nice touch.
To invoke the "Advanced Options" menu hit the Tilda key and type "preferences" without the quotes. The game will pause and go into windowed mode followed by the advanced options window popping up. This may take a few seconds to invoke so give it time. I attached some screen shots of it.

Heh, after each instal I always turned on all rendering options (esp. coronas). Amazing what Unreal software renderer could do on P200, especially when you remember that Q2's softrend could barely run on 320x200 on these specs :)

Yeah, I want new games using the same advanced configuration system :(