 The first game in the series, "Portal", was initially released alongside "Episode Two" in "The Orange Box" on October 10, 2007.The player controls a test subject named Chell as she moves through the laboratories of Black Mesa's primary rival, Aperture Science, completing various tests with a device that allows her to create linked portals in physical space.In the later stages of the game, the player battles GLaDOS, a corrupt artificial intelligence computer that monitors her every move.