The highly anticipated sequel to 2007's Game of the Year, Portal 2 is a hilariously mind-bending adventure that challenges you to use wits over weaponry in a funhouse of diabolical science. Using a highly experimental portal device, you’ll once again face off against a lethally inventive, power-mad A.I. named GLaDOS. And this time you won’t be alone. equel to the original Portal game -- the surprise add-on hit included in Valve Corporation's 2007 release The Orange Box -- Portal 2 continues the storyline from the first game, featuring both new and returning characters, and poses a range of new challenges.