Portal 2

Portal 2 is one of the greatest games ever made. That is not a controversial statement -- it is a near-universal consensus, and it is deserved. Valve's puzzle design is flawless, introducing mechanics at a steady pace that teaches through play and builds to solutions that make you feel like a genius. The portal gun remains one of gaming's most elegant mechanics, and the addition of gels, light bridges, and faith plates expands the possibility space without ever becoming overwhelming. The writing is exceptional -- GLaDOS, Wheatley, and Cave Johnson deliver some of gaming's most memorable dialogue, blending humor with surprisingly poignant character development. The separate co-op campaign is equally brilliant, with puzzles designed specifically for four-portal collaboration. The Source engine visuals are dated, but the art direction compensates through strong environmental storytelling. The campaign is not particularly long, and once puzzles are solved, replay value is limited outside of community test chambers. But every moment of Portal 2 is masterfully crafted. It is the rare game that achieves perfection within its scope.