It isn't an add-on, a mod or a new way of playing the world's most popular online shooter. Counter-Strike: Source is the same game that's known, loved and often responsible for gamers sitting motionless for days on end. But it's now been ported to Valve's new 3D engine, the Source engine, giving us our first glimpse of the technology that will be powering Half-Life 2.

For a company whose only other major release was the original Half Life, Valve has pushed the boundaries with fresh, bold gameplay that stays true to the legendary legacy.