One of the best games ever made
Graphics: 10/10
Stunningly beautiful. The environments are refreshing and at times very expansive and open. A welcome change from the confining test chambers of the first game.
Sound: 10/10
An amazing background soundtrack is complemented with witty and charming voice acting.
Story: 10/10
The story is simply amazing. Valve is exceptional at weaving a grasping story with enthralling characters. The dialogue is so flawless and at times actually made me laugh out loud at my computer.
Gameplay: 9.5/10
The concept is simple one portal here, one portal there and you have a path. Now throw in a box or two to put on a switch. Now throw in laser beams which need to be used to activate a switch. Add boxes which can direct the lasers. Gels are included, as are light beam bridges/shields, and turrets. All of these elements and more are thrown into portal 2's puzzles and though not use in every puzzle after introduced these elements are never completely forgotten. The co-op was a fresh pace too. Adding in two more portals created even more options for fun and more challenging puzzles. The only flaw I could find were the MASS amounts of load screens which plague the game. Essentially every puzzle you solve comes equipped with a load screen and it is very apparent.
Bottom Line: 9.5/10
Replayability: Very High
Final Thoughts: This is pretty much as good as a game can ever get. A charming story with equally charming characters. Mind bending puzzles which make you feel like a genius when you solve them. A co-op mode to challenge with your friends and amazing graphics and soundtrack. Portal 2 is already my pick for game of the year as it rightfully deserves it.