Portal 2

Portal 2 is the sequel to Portal. First hinted in the update made to Portal in March 2010 as part of the Portal ARG, it was announced on March 5, 2010 to be released in fall 2010, but was later announced on June 9, 2010 as delayed until an unspecified date in 2011, until it was said to be released on February 9, 2011. This date was again delayed to April 19.

Portal 2 was previewed in the twelve-page cover story of the April 2010 issue of Game Informer, revealing some plot details and new gameplay features. It has also been confirmed that GLaDOS is indeed still alive, and is slated to return as the main antagonist. In addition, Game Informer and other sources have also confirmed a co-op mode for up to two players with its own separate campaign. The co-op campaign will have its separate credits, and takes place after the single player story. Valve was also scheduled to unveil the Portal 2 World Premiere on June 14, at their E3 2010 press conference, but later canceled the showing of Portal 2 on the 14th through a humorous e-mail, to be replaced with a "surprise". The game was shown in the form of a demo at Valve's own booth instead, and on June 15, the first Portal 2 trailer was shown during the Sony press conference, with the "surprise" apparently being its release on the PlayStation 3 console, which was originally not the case.

Characters
Arranged by roles.
 * Chell
 * ATLAS and P-body
 * GLaDOS
 * Wheatley
 * Cave Johnson (voice only)
 * Caroline (voice only)
 * Space Core
 * Rick
 * Factual Core

Singleplayer Campaign

 * Chapter 1: The Courtesy Call
 * Chapter 2: The Cold Boot
 * Chapter 3: The Return
 * Chapter 4: The Surprise
 * Chapter 5: The Escape
 * Chapter 6: The Fall
 * Chapter 7: The Reunion
 * Chapter 8: The Itch
 * Chapter 9: The Part Where He Kills You

Cooperative Campaign

 * Test Course 1: Team Building
 * Test Course 2: Mass and Velocity
 * Test Course 3: Hard Light Surfaces
 * Test Course 4: Excursion Funnels
 * Test Course 5: Mobility Gels

Gameplay
Gameplay of Portal 2 is based on its predecessor Portal. New gameplay elements such as Gels, the Aerial Faith Plate and the Thermal Discouragement Beam were implemented in new puzzles.

Chell no longer wears the Advanced Knee Replacement, but instead suited in the new Aperture Science Long Fall Boots. Combat plays a slightly larger role than in the last game, seeing as Chell is always meeting with enemies along the way. And unlike Portal, Chell doesn't bleed after getting shot by turrets even though particle and decals for the blood are mentioned in the game files including the video for the [] where she can be seen getting shot. Chell finds out about it when examining a "virtified" door during Chapter 6 maps when Cave says that if a Test Subject would cut themself they'd notice that their blood is gasoline, Cave also explains that they had been shooting subjects with an invisible laser that's supposed to turn a test subject's blood into gasoline.

Co-op Campaign
Cooperative play is a new game mode introduced to Portal 2. The campaign features two characters, ATLAS and P-body. The two players must work together to pass tests and areas outside the test chambers. The developers implemented robotic characters in order to ease explanation of a respawning system, giving the story explanation that humans could not be trusted.

The same type of gameplay is used, with the addition of object-specific buttons and tools to aid in cooperative play, as well as 8 gestures.

Achievements and trophies
Portal 2 has 50 achievements and 51 trophies with a total of 1000 Gamerscore points, 42 bronze trophies, 5 silver trophies, 3 gold trophies and 1 platinum trophy.

Development
In 2007, Kim Swift stated that future Portal developments would depend on the community's reactions, saying, "We're still playing it by ear at this point, figuring out if we want to do multi-player next, or Portal 2, or release map packs." On January 31, 2008, Lombardi confirmed that "more Portal" would be forthcoming, and promised that the additional content would not just be "more puzzles"; an interview with Kim Swift on February 21, 2008 revealed that a full sequel, Portal 2, would be coming. Swift also stated that the team creating the Portal sequel were deciding upon the design they should implement and that a multiplayer Portal "from a technology standpoint is possible", though Swift had previously stated they tried a Portal multiplayer deathmatch variant, but admitted that "it's less fun than you'd think."

On June 10, 2008, Kotaku reported that Valve was seeking voice actors for the character role of Aperture Science CEO Cave Johnson and suggested that the second game may be a prequel to the Portal events. However, it was later suggested on Kombo.com it could be a sequel, with Johnson as another AI.

On April 8, 2011, lead writer Chet Faliszek gave an interview to Beefyjack where he discusses a variety of topics, including allusions to how Portal 2's story will fit into the overall Half Life universe and the secret to Valve's success when it comes to producing games being lots of playtesting.

On April 13, 2011, Doug Lombardi, Valve's VP of Marketing, posted details of Portal 2's PS3 Steam integration on the official US Playstation Blog. He noted that it will "offer cross-platform matchmaking, gameplay, friends, chat, and achievements" and will also allow players to save their progress, in both the co-op and single-player mode, to the Steam Cloud, which means gamers can continue any saved game on the PS3. Achievements will sync up as well. All in all, these features will, according to Lombardi, make the PS3 version of Portal 2 "the best console version of the game."

Reception
Portal 2 has received universally positive reviews and currently holds a 96/100 on Metacritic. Critics praised nearly every aspect of it, particularly its use of humor. Many also find the game's difficulty at just the right level, saying it's not so hard that it's frustrating, and yet hard enough that you get a sense of success after completing a level.

Portal 2 DLC #1
A currently unnamed DLC is being developed for Portal 2. Although little is known at this time, what is known is that it will launch across all platforms free of charge. It will also add a currently undefined challenge mode to both Single Player and Multiplayer.