Counter-Strike (also known as Half-Life: Counter-Strike) is a first-person shooter video game developed by Valve Corporation. It was initially developed and released as a Half-Life modification by Minh "Gooseman" Le and Jess Cliffe in 1999, before Le and Cliffe were hired and the game's intellectual property acquired. Counter-Strike was released by Valve on the Microsoft Windows platform in 2000.(wikipedia.org)