It appears GLaDOS was still alive after the conclusion of the first game!? What a twist! Our summer crush with the original Portal has now evolved into a full-blown relationship with Portal 2, and we aren't disappointed. Actually, it seems hardly anyone is ... well, except for the users who didn't appreciate Valve's conclusion to its ARG marketing stunt.

• Eurogamer (100/100): "Portal is perfect. Portal 2 is not. It's something better than that. It's human: hot-blooded, silly, poignant, irreverent, base, ingenious and loving. It's never less than a pure video game, but it's often more, and it will no doubt stand as one of the best entertainments in any medium at the end of this year. It's a masterpiece. "
• IGN (95/100): "Portal 2 makes the original look like the prototype it was. It's filled with a larger cast of characters vividly brought to life through brilliant writing and some of the best voice acting in video games. Its puzzles are challenging without being unreasonable, and, once you're finished with the single-player mode, one of the best co-operative experiences on the market awaits."
• Gamespot (90/100): "As you journey through the massive Aperture facility, it becomes clear that Portal 2 does not merely come after Portal. Instead, it radiates outward from its predecessor, simultaneously illuminating the world that gave rise to Portal and continuing the adventure that began there. The sense of novelty is diminished, but the thrill of exploration and puzzle-solving is still intoxicating, and it's amazing how Portal 2 manages to tell a better story with disembodied voices and spherical robots than most games can with full-on humans."
• Edge (90/100): "Valve has a pretty good record with the number two, but attempting to inflate Portal's perfectly formed package could easily have been a disaster. Naturally, the sequel doesn't feel as bracingly fresh as the 2007 game, but it's precisely the sort of dizzying follow-up the original deserves."