Portal 2 was made by the indie company Valve and is the second and last game in the Portal series.
Portal 2 is a first person puzzle game where you play as the test subject Chell in the Aperture Science Facility. In the first game, Portal, you were testing the portal gun which does exactly what it sounds like. It shoots two different portals, orange and blue. In one portal, out the other. You team up with a little robot name Wheatley, who helps you take down the evil AI GLaDOS who you thought you defeated in the last game, but is revealed to be alive.
I really like this game, and just the Portal series all together. But, the thing about the first Portal game, is that no one expected the game to be such a hit. It was made by a small team of developers because they needed a short little game to put in a game bundle. But on Portal 2, they got almost the entire company working on it. Where the first game was just a puzzle game with some great story elements, the second was story driven with some puzzles thrown in here and there. But in the end, I would definitely recommend this game.