The Orange Box is a five-game collection of best-selling Valve hits and anticipated new releases. The most recognizable games in the package are 2004's critically acclaimed Half-Life 2 and its first two expansion packs, Episode One and Episode Two. They are joined by the standalone puzzle game, Portal, and the team-based online shooter, Team Fortress 2. Half-Life 2 continues the saga of scientist Gordon Freeman, who finds himself in a world overrun by an alien army known as the Combine. One of the key features in Half-Life 2 and its expansions is the use of physics to interact with the environment, whether it's pushing cinder blocks to create a staircase or using a gravity gun to hoist and then slam objects into enemies. Freeman will interact with several friendly characters as well as drive an assortment of vehicles in his quest to defeat the ruthless Combine.<br><br>Portal is a 3D puzzle game played from a first-person perspective. The object is to advance through a series of rooms by using a gun to create a means of escape. Instead of lasers or bullets, the gun fires one of two opposing portal types: orange and red. One could be used as an entrance, while the other used as an exit. Portals can be fired on most surfaces, and the gun can also be used to pick up and toss objects. Storage and weighted "companion" cubes found within rooms are creatively used to activate switches, knock out security droids, and more. Turret guns, toxic liquid, crushing walls, and other hazards must also be avoided throughout play. A sarcastic, female-voiced computer will monitor your performance and serves as a droll guide for each area. In addition to the main game, players can unlock both a challenge and an advanced mode for more deviously designed puzzles and goals.<br><br>Team Fortress 2 pits two rival construction crews against each other on six themed maps. Nine classes are available when forming a team: Pyro, Heavy, Spy, Scout, Sniper, Medic, Engineer, "Demoman," and Soldier. Each class offers unique abilities and equipment to complete objectives, from a medic's healing powers to a spy's disguises for eluding detection. Three play modes include Capture-the-Flag, Control Point, and Territorial Control. Capture-the Flag involves retrieving a briefcase from the enemy's base before the opposition does the same. Control Point has teams maintaining control over four areas on a map, two of which are in contention, before one side can capture the rival team's base. Territorial Control features five contested areas, allowing for a more open play style. Team Fortress 2 is further distinguished by its distinctive, cartoon-like visual style as well as its detailed stat tracking.