Portal 2 can certainly be considered one of the most successful games of 2011. If Portal managed to introduce a new gameplay style with many puzzles, then Portal 2 exceeded all the previous achievements and expanded the whole thing. If you ask me (or almost anyone else), then Portal 2 is not just about puzzles - there is so much more to this game than it may seem at first, but of course the puzzles are also a great part of the game.
The thing that I enjoyed the most about Portal 2, were the constant comments the player can (must) hear during the adventure through the Aperture Science Enrichment Center. The amount of jokes and sarcasm is just insane! The game deserves an award just for those laughs that it offers the player. My favourite comments of course came from GLaDos - a malevolent core that has been in charge of the facilities for years, and was the main antagonist of the first Portal game. In Portal 2, though, she is trying to get her revenge by keeping up the testing. During all those tests, she also does not forget to make remarks about your past, appearance, personality etc. Truly a genius machine, I must say.
Moving on from the hilariousness of the game, it should be said that the game also does not lose in the gameplay part. People who loved Portal will probably enjoy this one even more, with many new possibilities and challenges. For example, Valve added some interesting features to this game, such as laser platforms, gravitational beams and the experimental gel. All of those offer you new solutions to previously unsolvable problems, and you will have to use all of those features to your advantage, if you want to put an end to the rampage of the machines, and play through a game at least twice the length of original Portal game.
If we talk about Portal 2, it is important that you know the story of Portal. It all started with the main character being a test subject in the Aperture Science Enrichment Center, that was under the control of GLaDOS. At first the player was obediently working his/her way through various deadly and puzzling rooms, in order to receive a cake as a prize. As you went on , though, there are more and more signs of something bad happening. The facilities turn out to be a prison for the main character, forced to test forever, or at least until the 'expiry'. In order to complete the puzzles, you are given a portal gun in the very beginning. What is a portal gun? It is a special weapon that can shoot blue and orange charges, creating a portal upon impact. A very convenient thing, must be said. The difficulty comes when you realize that the portals can only be created on specific surfaces. Also, you can have only two portals at a time - to avoid a paradox. Anyway, using the portal gun, you can use the physical laws to your advantage, doing things that would normally be impossible, like achieving extremely high speeds and falling thousands of meters without dying. That is a very innovative idea.
Of course, when talking about modern games, we have to mention the graphics. Even though the game isn't very demanding, it offers a big variety of graphical effects to the player, proving that it is a game of the year 2011. Perhaps not as realistic as games like Battlefield 3, but it is beautiful in it's own way. The small let-down, that is actually absolutely not important, is the design of the main character, who can only be seen through portals, due to the gameplay being in first-person. The movements of the protagonist are not well-made, but that shouldn't even matter, because without seeing the player character, the movements are just perfect.
I would also like to mention the ending - Portal 2 managed to offer plot twists right till the end, and I just loved them. I will not spoil the ending, but I have to mention that I was satisfied. The credit song was also very funny, with lots of sarcasm. The voice of GLaDOS will probably remain as my favourite voice of all times in games. If I was to add something to this game, then it would be the main character's voice, because without it, the "conversation" or rather monologues seem unfinished.
In conclusion, I would say that this game definitely deserved all the positive reviews it has received, and it is not a surprise, that I will also give it a strong 10. If I was to choose the game of the year, I would put it in the second place, right behind Skyrim, but with a very small difference in enjoyment. Portal 2 is truly a game that everyone should try, and most will love. I recommend it to everyone - from RPG fans to FPS fans, from sports games fans to puzzle lovers. It really is a game that has made history and will be remembered for years.