Full installer of Covert Strike Force v1.2b4, coop mod for HL1. Enjoy.
From the maker of Thai's Contra - Force Mod.
The Covert Strike Force (CSF) is a Half-Life Modification based on the Realistic Cooperative. You and your teammates will have to act together strategically to fight the enemy monsters.
Features that CSF will contain are: Buying System, Cash system, bayonets, Controlable Helicopter and much much more...