Portal 2 is an exquisite marriage of plot and gameplay, celebrated in single- and multiplayer.
The reason why Portal 2 is such an awesome game is that the story is so cleverly written and brilliantly told by establishing a seamless relationship between gameplay and the developer-authored plot. This game is an outstanding peace of storytelling and it is completely aware of the gameplay conventions and their narrative potential. It's actually really simple. The plot of Portal 2 draws its strength from the gameplay and doesn't merely try to fit gameplay into an already finished authored plot which justifies the gameplay.
This game utilizes environmental storytelling in an immensely intelligent way and delivers hilarious dialogues between the funny new characters. On top of it all, both singleplayer mode and multiplayer mode have a separated story, that is incredibly well written. It's nice to see that the co-op mode got equally much commitment as the singleplayer and isn't only treated as an optional way to progress the story like in Gears of War 2 where one could step into the role of a character who else would have been played by the AI instead.
Anyways, to come back to the environmental storytelling mentioned earlier, Portal 2 occasionally gives the player some `behind the scenes` material of the test chambers with writings on walls from former participants. It's just amazing to see all the little stories your surroundings try to tell you and because gameplay determines how the player interacts with the environment, stories told through the environment must inevitably be filtered through gameplay. And Portal 2 does it effortlessly.
Portal 2 is a great example why focussing on gameplay can produce better stories, instead of concentrating too much on how stories can make better games *coughL.A.Noirecough*. Too many games tend to be like straight-lined author-controlled movies, though games have so much potential in an utterly different direction. Imagine playing chess. Chess mainly is a story that's written while you play it and that's relatively Portal 2's approach.
At it s core Portal 2 is an obstacle course at every level as the player has to utilize his mental and physical skill to circumnavigate the levels' obstacles. It's a challenge of how players perceive things to solve a problem, ultimately leading to increase their empathy with the playable avatar whithin progress. The game seamlessly blends story and gameplay, but relies more on gameplay.
While the singeplayer took me about 15 hours on my first playthrough, the co-op mode was about 10 hours long, but it eventually depends on how easily you can adapt to your environment in the game to solve the puzzles. I've played many games, but Portal 2 is one I'll remember for never ceasing to impress and making me laugh, from start to one of the best and funniest conclusions in gaming history. The game features hilarious dialogues and situations, funny likable characters, intuitive controls, a cleverly written and brilliantly told narrative no matter if played alone or with a friend. Portal 2 is a highly innovative, but also simple puzzleshooter, that is refreshengly nonviolent for the genre and demands often more teamwork than other titles which call themselves tactical shooters, as you'll give your friend more suggestions, advice and lead than in many of the aforementioned games. Hopefully Portal 2 gets many DLCs because I loved every minute of playing it.