As typical of Valve Software, a very short press release from the makers of the Half-Life series announced a partnership with Turtle Rock Studios to create Left 4 Dead, a co-operative multiplayer action game.

“By leveraging its industry-leading AI technology and years of Counter-Strike development experience, Turtle Rock is building upon the elements that make Counter-Strike successful and applying them to Left 4 Dead,” said Gabe Newell, co-founder and president of Valve. “What Counter-Strike did for multiplayer action games, Left 4 Dead will do for co-op games.”

Left 4 Dead is being developed using the “most advanced version” of the Source engine and introduces version 2 of Turtle Rock’s AI technology. The game is set for release on PC sometime next year.