A user made mod by Flayra for half life, who set up his own company with the reputation he gained from it
Involves two teams, the Kharaa (alien) and the TSA (Marines) Who battle it out on base building, or combat maps. They gain upgrades and become more powerful
Has a large fan based community with many user made levels.
Dammit, im bored...Im gonna go play natural selection
Natural Selection Kicks ass
Natural Selection is much better than Counter Strike