The Witchaven PREF.DAT contains settings that can be changed within the game (as opposed to in the configuration utility), and is written to as well as read from in the main game EXE.
|0||INT16||Extra gore on (1) / off (0)|
|2||INT16||brightness (0-8) (Gamma correct, but game only loads and doesn't apply it)|
|4||INT16||gbrightness (0-8) (As above, but game only applies it after doing lighting FX like lightning)|
|6||INT16||Sound effects volume (0-16)|
|8||INT16||Music volume (0-16)|
|10||INT16||Difficulty setting (1-4)|
The Witchaven source code was consulted.