Addon "Ghosts of War": RtCW Singleplayer
Authors: Dan & Jex

Installation and launching:

1) Unzip archive in your Return to Castle Wolfenstein directory (NOT in main!);
in "Ghosts of War" folder:

ghostsofwar.bat
ghostsofwar.pk3

2) Start ghostsofwar.bat

Problems: on some versions "Return to Castle Wolfenstein" can disappear textures.