Portal 2

Portal 2 is a puzzle-platformer developed and published by Valve Corporation. It is the second installment in the Portal series and a part of the Half-Life series. It was released in 2011 for the Microsoft Windows, Mac OS X, PlayStation 3 and Xbox 360.
== Plot ==
=== Single-player Campaign ===
Chell, the returning protagonist from Portal, is awakened by a robotic voice in what appears to be a motel room. After a cognitive test, Chell is put back to sleep, where she awakens many years later. Wheatley, a personality core, begins to move the room, which is actually a large shipping container, through a warehouse where he destroys a wall. Wheatley then requests Chell to retrieve a portal gun. Beginning with a deteriorated Test Chamber 00, she repeats test chambers that she had gone through years before.
At Test Chamber 08, Chell retrieves the portal gun. Wheatley and herself then go to the destroyed chamber of GLaDOS to activate an escape pod, however, they accidentally turn GLaDOS, who has not forgiven Chell for "murdering" her, back on. GLaDOS throws Wheatley away and puts Chell back into new tests.
As Chell continues through the tests presented by GLaDOS, Wheatley is shown to be severely damaged, but still operational. In Test Chamber 17, Wheatley disrupts GLaDOS tests and directs Chell on escaping through the back parts of Aperture Science. After escaping GLaDOS' grasp, Wheatley decides that to stop the rampaging artificial intelligence, they will need to deactivate her neurotoxin gases and her turret production. 
After replacing the normal turret template with a broken one and destroying the neurotoxin gases, Chell performs a core transfer, placing Wheatley with GLaDOS' body. However, as Wheatley is allowing Chell to leave Aperture Science, he decides that testing shall continue and, after angered by GLaDOS (kept alive by a potato battery), destroys the escape elevator causing it drop Chell and GLaDOS into the remains of the original Aperture Science building, Aperture Science Innovators.
As Chell completes tests in Aperture Science Innovators to follow the catwalks to escape, she finds GLaDOS still alive and places the potato on the end of the portal gun. As Chell completes further tests, accompanied by the pre-recorded voice of Cave Johnson, founder and CEO of Aperture Science Innovators, GLaDOS gradually begins to remember her former self, Caroline, who had been Cave Johnson's assistant.
Chell and GLaDOS return to Aperture Science to learn that Wheatley has begun testing with turrets inserted into cubes. Upon learning of Chell's return, Wheatley sets to putting her into more tests. As GLaDOS formulates a plan to escape Wheatley, he learns of the Co-operative Testing Initiative, consisting of robotic partners ATLAS and P-body, and tries to kill Chell. 
After escaping from Wheatley, Chell and GLaDOS head Wheatley's chamber to attempt a second core transfer. However, Wheatley destroys the core transfer assistant's confirmation button, causing Chell to open a portal on the moon, which Cave Johnson reveals earlier is an excellent portal conductor. This pulls both Chell and Wheatley through the portal located under Wheatley's body. GLaDOS then performs core transfer, launching Wheatley into space, however, GLaDOS pulls Chell back through the portal. GLaDOS then, despite Caroline's impact making Chell pull her back through the portal, promptly deletes Caroline's part of the artificial intelligence. GLaDOS then states that Chell is too much of a nuisance to kill and gives Chell her freedom.
=== Co-operative Campaign ===
ATLAS, a modified personality core, and P-body, a modified turret, are the two test subjects of the Co-operative Testing Initiative. GLaDOS sets the two robots to perform tests that can only be completed by two test subjects working together. At the end of each section of testing, GLaDOS sends the robots outside of the testing facilities to locate compact discs "innocently" left laying around by the humans.
When ATLAS and P-body find the final compact disc, GLaDOS reveals that the discs allowed her to gain control over the entire facility and can access a vault in the Aperture Science Innovators buildings, located under the existing Aperture Science facility. After completing an assortment of tests to reach the vault and unlock it, the pair of robots learn that they still cannot open the vault. Upon performing similar actions to that on the vault, the vault opens and GLaDOS congratulates the two. The artificial intelligence then self-destructs the pair, as it is the only way to return them to the hub area, for further testing.
== Gameplay ==
Portal 2 is played in the exact same manner as its predecessor, Portal. In single-player, Chell can place two portals, one blue and one orange, on any material that is white. There are new objects that Chell can interact with, such as Excursion Funnels and Hard Light Bridges.
In co-operative, ATLAS and P-body are outfitted with their own portal guns. ATLAS' portal gun can shoot a blue and an indigo portal, whereas P-body can shoot an orange and a red portal. This allows for a maximum of four portals. 
== Reception ==
Category:Games released for PC
Category:Games released for Mac
Category:Games released on the PlayStation 3
Category:Games released on the Xbox 360
Category:Games by Valve Corporation