To start the game, you'll need the original resurces of a licensed copy of
S.T.A.L.K.E.R. - Call of Pripyat and/or S.T.A.L.K.E.R. - Clear Sky.

You'll need these directories from your S.T.A.L.K.E.R. game distribution:
 * levels
 * localization
 * mp
 * patches
 * resources

Put them in this directory:
 * ~/.local/share/GSC Game World/S.T.A.L.K.E.R. - Call of Pripyat/
   (For Call of Pripyat)
 * ~/.local/share/GSC Game World/S.T.A.L.K.E.R. - Clear Sky/
   (For Clear Sky)

!!!Attention!!!
These paths must be created by you first. Pay attention to the spaces,
they'll need to be properly escaped. For example:
mkdir -p ~/.local/share/'GSC Game World'/'S.T.A.L.K.E.R. - Call of Pripyat'