Empires Mod is a HalfLife 2 mod which installs and runs well in COG-8.1.4/linux.
You will need a pre-existing HalfLife 2 installation to use this mod -- I tested
this mod with Steam using HalfLife 2 as the qualifying dependency.
Installation is straightforward;
download the Empires Mod installer executable
install the mod into the same bottle you have Steam/HalfLife 2 installed into - the installer seems to get the paths right
*play the game
Gets a silver straight up, but appears to be running at gold level - more
time with gameplay/testing required yet...
Cheers!