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WikiPedia: Portal_2 //www.amazon.com/dp/B004XMZZKQ http://www.computerandvideogames.com/253854/news/t... http://www.computerandvideogames.com/288474/news/p... http://g4tv.com/games/xbox-360/63787/portal-2/arti... http://www.gamasutra.com/view/feature/6198/rewardi... http://www.gameinformer.com/b/news/archive/2010/03... http://ps3.ign.com/articles/109/1098375p1.html http://xbox360.ign.com/articles/111/1118382p1.html http://technolog.msnbc.msn.com/_news/2010/09/08/50... http://multiplayerblog.mtv.com/2011/04/29/behold-s...