Portal

Portal
Portal is a 2007 single-player first-person puzzle-platform video game developed by Valve Corporation. The game was released in a bundle package called The Orange Box for Microsoft Windows andXbox 360 on October 9, 2007,[3] [4] and for the PlayStation 3 on December 11, 2007.[7] The Windows version of the game is available for download separately through Valve's content delivery systemSteam[2] and was released as a standalone retail product on April 9, 2008.[9] A standalone version called Portal: Still Alive was released on the Xbox Live Arcade service on October 22, 2008; this version includes an additional 14 puzzles. A Mac OS X version was released as part of the Mac-compatible Steam platform on May 12, 2010.[11]

The game primarily comprises a series of puzzles that must be solved by teleporting the player's character and simple objects using "the handheld portal device", a device that can create inter-spatialportals between two flat planes. The player-character, Chell, is challenged by an artificial intelligence named GLaDOS (Genetic Lifeform and Disk Operating System) to complete each puzzle in the Aperture Science Enrichment Center using the portal gun with the promise of receiving cake when all the puzzles are completed. The game's unique physics allows momentum to be retained through portals, requiring creative use of portals to maneuver through the test chambers. This gameplay element is based on a similar concept from the game Narbacular Drop; many of the team members from the DigiPen Institute of Technology who worked on Narbacular Drop were hired by Valve for the creation of Portal.

Portal was acclaimed as one of the most original games of 2007, despite being considered short in length. The game received praise for its unique gameplay and darkly humorous story. It received acclaim for the character of GLaDOS, voiced by Ellen McLain in the English-language version, and the end credits song "Still Alive" written by Jonathan Coulton for the game. Not counting sales through Steam, over four million copies of the game have been sold since its release. The game's popularity has led to official merchandise from Valve including plush Companion Cubes, as well as fan recreations of the cake and portal gun. A sequel, Portal 2, was released in 2011, adding several new gameplay mechanics and a cooperative multiplayer mode.[12]

[edit] Characters
The game features two characters: the player-controlled silent protagonist named Chell, and GLaDOS (Genetic Lifeform and Disk Operating System), a computer artificial intelligence that monitors and directs the player. In the English-language version, GLaDOS is voiced by Ellen McLain, though her voice has been altered to sound more mechanical. The only background information presented about Chell is given by GLaDOS; the credibility of these facts, such as Chell being adopted, an orphan, and having no friends, is questionable at best, as GLaDOS is a liar by her own admission. In the "Lab Rat" comic created by Valve to bridge the gap between Portal and Portal 2, Chell's records reveal she was ultimately rejected as a test subject for having "too much tenacity"—the main reason Doug Rattman, a former employee of Aperture Science, moved Chell to the top of the test queue.[20] [21]

[edit] Setting
Portal takes place in the Enrichment Center for Aperture Laboratories—also known as Aperture Science—which is the fictional research corporation responsible for the creation of the portal gun. According to information presented in Portal 2, the location of the complex is in the Upper Peninsula of Michigan. Information about the company, developed by Valve for creating the setting of the game, is revealed during the game and via the real-world promotional website.[22] According to the Aperture Science Web site, Cave Johnson founded the company in 1953 for the sole purpose of making shower curtains for the U.S. military. However, after becoming mentally unstable from lunar poisoning in 1978, Johnson created a three-tierresearch and development plan to make his organization successful. The first two tiers, the Counter-Heimlich Maneuver (a maneuver designed to ensure choking) and the Take-A-Wish Foundation (a program to give the wishes of dying children to unrelated, entirely healthy adults), were commercial failures and led to an investigation of the company by the U.S. Senate. However, when the investigative committee heard of the success of the third tier, a man-sized ad-hoc quantum tunnel through physical space with possible applications as a shower curtain, it recessed permanently and gave Aperture Science an open-ended contract to continue its research. The development of GLaDOS, an artificially intelligent research assistant and disk-operating system, began in 1986 in response to Black Mesa's work on similar portal technology.[23] A presentation seen during gameplay reveals that GLaDOS was also included in a proposed bid for de-icing fuel lines, incorporated as a fully functional disk-operation system that is arguably alive, unlike Black Mesa's proposal, which inhibits ice, nothing more.<sup class="reference" id="cite_ref-gi_portal_hl_23-0" style="line-height:1em;">[24] Roughly thirteen years later, work on GLaDOS was completed and the untested AI was activated during the company's first everbring-your-daughter-to-work day in May 2000.<sup class="reference" id="cite_ref-gi_apsci_history_21-1" style="line-height:1em;">[22] Immediately after activation, the facility was flooded with deadly neurotoxin by the AI. Events of the first Half-Life game occur shortly thereafter, presumably leaving the facility forgotten by the outside world due to apocalyptic happenings. Wolpaw, in describing the ending of Portal 2, affirmed that the Combine invasion from Half-Life 2 occurred during Portal ' s events.<sup class="reference" id="cite_ref-pcgamer_p2_wolpaw_interview_24-0" style="line-height:1em;">[25]

<p style="margin-top:0.4em;margin-bottom:0.5em;line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">The areas of the Enrichment Center that Chell explores suggest that it is part of a massive research installation. At the time of events depicted in Portal, the facility seems to be long-deserted, although most of its equipment remains operational without human control.<sup class="reference" id="cite_ref-1up_pc_review_25-0" style="line-height:1em;">[26] Aperture Science exists in the Half-Life universe,<sup class="reference" id="cite_ref-gamespotarticle1_15-1" style="line-height:1em;">[16] <sup class="reference" id="cite_ref-gi_portal_hl_23-1" style="line-height:1em;">[24] with the events of Portal occurring sometime between the story of Half-Life and Half-Life 2.<sup class="reference" id="cite_ref-26" style="line-height:1em;">[27] Aperture Science Inc. is also mentioned during Half-Life 2: Episode Two, in which Aperture's icebreaker ship Borealis is said to have disappeared under mysterious circumstances, along with the crew and part of its drydock.<sup class="Template-Fact" style="line-height:1em;white-space:nowrap;">[citation needed] During its development, Half-Life 2 featured a chapter set on the Borealis, but this was abandoned and removed before release.<sup class="reference" id="cite_ref-raisingthebar_27-0" style="line-height:1em;">[28]

[edit] Plot
<p style="line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">Portal ' s plot is revealed to the player via audio messages from GLaDOS and side rooms found in the later levels. According to The Final Hours of Portal 2, the year is established to be "somewhere in 2010" — twelve years after its abandonment. The game begins with protagonist Chell waking up from a stasis bed and hearing instructions and warnings from GLaDOS about the upcoming test experience. This part of the game involves distinct test chambers that, in sequence, introduce players to the game's mechanics. GLaDOS's announcements serve not only to instruct Chell and help her progress through the game, but also to create atmosphere and develop the AI as a character.<sup class="reference" id="cite_ref-commentary_12-3" style="line-height:1em;">[13] Chell is promised cake and grief counseling as her reward if she manages to complete all the test chambers.<sup class="reference" id="cite_ref-gamespy_pc_review_28-0" style="line-height:1em;">[29]

<p style="margin-top:0.4em;margin-bottom:0.5em;line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">Chell proceeds through the empty Enrichment Center, interacting only with GLaDOS. Over the course of the game, GLaDOS's motives are hinted to be more sinister than her helpful demeanor suggests. Although she is designed to appear helpful and encouraging, GLaDOS's actions and speech suggest insincerity and callous disregard for the safety and well-being of the test subjects. The test chambers become increasingly dangerous as Chell proceeds, and GLaDOS even directs Chell through a live-fire course designed for military androids as a result of "mandatory scheduled maintenance" in the regular test chamber, as well as having test chambers flooded with deadly liquid. In another chamber, GLaDOS boasts about the fidelity and importance of the Weighted Companion Cube, a waist-high crate with a single large pink heart on each face, for helping Chell to complete the chamber. However, GLaDOS then declares that it "unfortunately must be euthanized" in an "emergency intelligence incinerator" before Chell can continue.<sup class="reference" id="cite_ref-1up_pc_review_25-1" style="line-height:1em;">[26] Some of the later chambers include automated turrets with child-like voices (also voiced by McLain) that fire at Chell, only to sympathize with her after being disabled ("I don't blame you" and "No hard feelings").<sup class="reference" id="cite_ref-eurogamer_pc_review_29-0" style="line-height:1em;">[30] <sup class="reference" id="cite_ref-ign_pc_review_30-0" style="line-height:1em;">[31]

<p style="margin-top:0.4em;margin-bottom:0.5em;line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">After Chell completes the final test chamber, GLaDOS congratulates her and prepares her "victory candescence", maneuvering Chell into a pit of fire. As GLaDOS assures her that "all Aperture technologies remain safely operational up to 4,000 degrees [sic] kelvin", Chell escapes with the use of the portal gun and makes her way through the maintenance areas within the Enrichment Center.<sup class="reference" id="cite_ref-wellplayed_31-0" style="line-height:1em;">[32] GLaDOS becomes panicked and insists that she was only pretending to kill Chell, as part of testing. GLaDOS then asks Chell to assume the "party escort submission position", lying face-first on the ground, so that a "party associate" can take her to her reward. Chell continues forward. Throughout this section, GLaDOS still sends messages to Chell and it becomes clear that she has become corrupt and may have killed everyone else in the center. Chell makes her way through the maintenance areas and empty office spaces behind the chambers, sometimes following graffiti messages which point in the right direction. These backstage areas, which are in an extremely dilapidated state, stand in stark contrast to the pristine test chambers. The graffiti includes statements such as "the cake is a lie" and pastiches of Emily Dickinson's poem "The Chariot", Henry Wadsworth Longfellow's "The Reaper and the Flowers", and Emily Brontë's "No Coward Soul Is Mine", mourning the death of the Companion Cube.<sup class="reference" id="cite_ref-commentary_12-4" style="line-height:1em;">[13]

<p style="margin-top:0.4em;margin-bottom:0.5em;line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">GLaDOS attempts to dissuade Chell with threats of physical harm and misleading statements claiming that she is going the wrong way as Chell makes her way deeper into the maintenance areas. Eventually, Chell reaches a large chamber where GLaDOS's hardware hangs overhead. GLaDOS continues to plead with Chell, but during the exchange one of GLaDOS' personality core spheres falls off; Chell drops it in an incinerator. GLaDOS reveals that Chell has just destroyed the morality core, which the Aperture Science employees allegedly installed after GLaDOS flooded the enrichment center with a deadly neurotoxin, and goes on to state that now there is nothing to prevent her from doing so once again. A six-minute countdown starts as Chell dislodges and incinerates more pieces of GLaDOS, while GLaDOS attempts to discourage her both verbally with a series of taunts and increasingly juvenile insults and physically by firing rockets at Chell. After she has destroyed the final piece, a portal malfunction tears the room apart and transports everything to the surface. Chell is then seen lying outside the facility's gates amid the remains of GLaDOS. One of the final scenes is changed through a patch of the PC version that was made available a few days before Portal 2 ' s announcement; in this retroactive continuity, Chell is dragged away from the scene by an unseen entity speaking in a robotic voice, thanking her for assuming the party escort submission position.<sup class="reference" id="cite_ref-gi_portal_hl_23-2" style="line-height:1em;">[24] <sup class="reference" id="cite_ref-shacknews_update_2_32-0" style="line-height:1em;">[33]

<p style="margin-top:0.4em;margin-bottom:0.5em;line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">The final scene, after a long and speedy zoom through the bowels of the facility, shows a mix of shelves surrounding a Black Forest cake<sup class="reference" id="cite_ref-german_chocolate_33-0" style="line-height:1em;">[34], and the Weighted Companion Cube. The shelves contain dozens of other personality cores, some of which begin to light up before a robotic arm descends and extinguishes the candle on the cake.<sup class="reference" id="cite_ref-gi_p2_reveal_34-0" style="line-height:1em;">[35] As the credits roll, GLaDOS delivers a concluding report: the song "Still Alive", which declares the experiment to be a huge success.<sup class="reference" id="cite_ref-portal_the_skinny_35-0" style="line-height:1em;">[36]

Portal 2
<p style="line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">Portal 2 is a first-person puzzle-platform video game developed and published by Valve Corporation. It is the sequel to Portal (2007) and was released on April 18, 2011 for Microsoft Windows, Mac OS X, PlayStation 3, and Xbox 360. The retail versions of the game are distributed by Electronic Arts, while digital distribution of the Windows and OS X versions is handled by Valve's content delivery service, Steam. Portal 2 was announced on March 5, 2010, following a week-long alternate reality game based on new patches to the original game. The sequel's release on Steam was preceded by a second multi-week alternate reality game, the Potato Sack, involving 13 independently-developed titles which culminated in a distributed computing spoof to release Portal 2 several hours early.

<p style="margin-top:0.4em;margin-bottom:0.5em;line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">Like its predecessor, Portal 2 primarily comprises a series of puzzles that must be solved by teleporting the player's character and simple objects using the "portal gun", a device that can create inter-spatial portals between two flat planes. The game's modified physics engine allows momentum to be retained through these portals, which must be used creatively to maneuver through the game's challenges. In addition to retaining most of the original Portal ' s gameplay elements, the sequel added new features, including tractor beams, laser redirection, bridges made of light, and paint-like gels that give surfaces special properties (e.g. accelerating the player's speed, allowing them to jump higher). These gels were created by the team from the Independent Games Festival-winning DigiPenstudent project Tag: The Power of Paint.

<p style="margin-top:0.4em;margin-bottom:0.5em;line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">Within the single-player campaign, the player returns as the human Chell, having awakened from stasis after many years. Chell must navigate the now-dilapidated Aperture Science Enrichment Centerwith the portal gun while the facility is rebuilt by the reactivated GLaDOS, an artificially-intelligent computer that appeared in Portal as its main antagonist. The storyline is longer than that of Portal ' s, and introduced new characters, including: Wheatley, a personality core voiced by Stephen Merchant; and recordings of Cave Johnson, the deceased CEO of Aperture Science voiced by J. K. Simmons.Ellen McLain reprised the role of GLaDOS. Jonathan Coulton and The National produced one song each for the game. Portal 2 also includes a two-player co-operative mode, in which the robotic player-characters Atlas and P-Body are each given a portal gun and are required to work together to solve test chambers specifically designed to require co-operation. Valve provided post-release support for the game, including additional downloadable content and a simplified map editor to allow players to create and share test chambers with others.

<p style="margin-top:0.4em;margin-bottom:0.5em;line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">Though many reviewers were initially concerned about the difficulty of expanding Portal into a full sequel, critics universally praised Portal 2. The game's writing, pacing, and dark humor were highlighted as stand-out elements, with critics applauding the voice work of McLain, Merchant, and Simmons. Reviews also highlighted the new gameplay elements, the game's challenging but surmountable learning curve, and the additional co-operative mode. Numerous gaming journalists ranked Portal 2 among the top games of 2011, including several naming it their Game of the Year.

Plot
<p style="line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">Portal 2 follows the player-character Chell after the end of Portal, in which she destroys the rogue artificial intelligence construct GLaDOS that ran the Aperture Science Enrichment Center where the game is set. In Portal ' s backstory, Aperture Science conducted experiments to determine whether human subjects could navigate dubiously safe "test chambers", until GLaDOS killed the scientists with a neurotoxin. The ending of the first game, retroactively patched just prior to the sequel's official announcement, shows Chell being dragged away from the remains of GLaDOS by an unseen figure with a robotic voice, later identified by writer Erik Wolpaw as the "Party Escort Bot."<sup class="reference" id="cite_ref-nationalpost_interview_22-0" style="line-height:1em;">[23] A promotional comic shows that an estranged Aperture Science employee placed Chell into suspended animation for an indefinite amount of time, in an effort to save her life.

<p style="margin-top:0.4em;margin-bottom:0.5em;line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">The Portal series shares a universe with the Half-Life series. Portal takes place between Half-Life and Half-Life 2,<sup class="reference" id="cite_ref-kotaku1_23-0" style="line-height:1em;">[24] and Portal 2 is set "a long time after" its predecessor (presumably years later).<sup class="reference" id="cite_ref-24" style="line-height:1em;">[25]

[edit] Single-player campaign
<p style="line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">Chell wakes to find herself in a stasis chamber modeled after a motel room. An announcer's voice guides her through a cognitive test before she is put back to sleep. When she awakens again, many years have passed, and the Aperture Science facility has become dilapidated and overgrown. Wheatley (Stephen Merchant), a personality core, moves the room—located in one of hundreds of shipping containers in a giant warehouse—and the pair attempt to escape via the test chambers.<sup class="reference" id="cite_ref-ign_30min_25-0" style="line-height:1em;">[26] <sup class="reference" id="cite_ref-26" style="line-height:1em;">[27] In the process, they discover the dormant GLaDOS (Ellen McLain) and accidentally reactivate her. GLaDOS, who has not forgiven Chell for "murdering [her]" years ago,<sup class="reference" id="cite_ref-gi_reveal_4-7" style="line-height:1em;">[5] separates Chell from Wheatley and begins rebuilding the facility.<sup class="reference" id="cite_ref-27" style="line-height:1em;">[28] <sup class="reference" id="cite_ref-guardian_e3_28-0" style="line-height:1em;">[29]

<p style="line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">After they have landed deep underground, GLaDOS is abducted by a bird, while Chell explores the decommissioned section of the facility where she finds herself. From there, she ascends through a series of old test chambers in chronological order (with the decor slowly changing from 1950's styles to ones more similar to the style seen early in the story and in the first Portal game). As she navigates the chambers, she regularly receives audio recordings of Aperture Science's CEO, Cave Johnson (J. K. Simmons).<sup class="reference" id="cite_ref-vg247_interview_30-0" style="line-height:1em;">[31] The player learns that Johnson became increasingly embittered and deranged as his company lost money and prestige, leading to him being fatally poisoned by moon dust (which, coincidentally, is a "great portal conductor").<sup class="reference" id="cite_ref-31" style="line-height:1em;">[32] His assistant, Caroline (McLain), became a test subject for a mind-to-computer transfer experiment, ultimately becoming part of GLaDOS. Chell reunites with GLaDOS, forming a partnership to stop Wheatley before his incompetence destroys the complex, while GLaDOS struggles with the revelation about Caroline.<sup class="reference" id="cite_ref-thereunion_32-0" style="line-height:1em;">[33] GLaDOS begins testing Chell in a series of new test chambers, until Wheatley helps Chell escape. The pair disable the neurotoxin and turret manufacturing plants before confronting GLaDOS a second time. Chell performs a "core transfer", replacing GLaDOS with Wheatley in the hardware "body" that controls the facility. He becomes intoxicated with power, and places GLaDOS's personality into a module powered by a potato battery. GLaDOS then claims to remember Wheatley's original purpose: she claims that he was originally designed to be "the dumbest moron who ever lived", producing illogical thoughts to hamper GLaDOS's decision-making processes in an attempt to make her less dangerous.<sup class="reference" id="cite_ref-globeandmail_quotes_29-0" style="line-height:1em;">[30] Wheatley angrily denies this, throwing Chell and GLaDOS down an elevator shaft into an abandoned area of the facility miles underground.

<p style="margin-top:0.4em;margin-bottom:0.5em;line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">Chell and GLaDOS return to the modern facility and face Wheatley, who is driven by GLaDOS's body to continue to test them.<sup class="reference" id="cite_ref-theitch_33-0" style="line-height:1em;">[34] Wheatley tricks Chell into a series of deathtraps. Chell escapes due to Wheatley's clumsiness and lack of logical thinking, and makes her way to his chamber.<sup class="reference" id="cite_ref-fastcompany_portal2_34-0" style="line-height:1em;">[35] In their final confrontation, Chell attaches three corrupt personality cores (Nolan North)<sup class="reference" id="cite_ref-35" style="line-height:1em;">[36] to the body that Wheatley inhabits, allowing GLaDOS to initiate a second core transfer and put herself back in control. However, just as Chell is about to conclude the core transfer, Wheatley reveals that he has booby-trapped the process. With the facility's reactor on the brink of meltdown, the roof collapses, revealing the night sky. Chell shoots a portal at the moon overhead, causing the vacuum of space to pull her and Wheatley through the other portal still inside the chamber.<sup class="reference" id="cite_ref-gamasutra_gdc2012_36-0" style="line-height:1em;">[37] GLaDOS pulls Chell back inside, where she falls unconscious, leaving Wheatley stranded in space, along with a corrupt, space-obsessed personality core.<sup class="reference" id="cite_ref-tpwhky_37-0" style="line-height:1em;">[38]

<p style="margin-top:0.4em;margin-bottom:0.5em;line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">When Chell awakens, GLaDOS explains that she learned valuable lessons about humanity from her Caroline persona.<sup class="reference" id="cite_ref-tpwhky_37-1" style="line-height:1em;">[38] She promptly deletes this aspect of her personality, reverting to her usual antagonistic attitude. She finally allows Chell to leave the facility, explaining that trying to kill Chell has proven so difficult that she has chosen to just let her go.<sup class="reference" id="cite_ref-gamasutra_wolpaw_interview_38-0" style="line-height:1em;">[39] The game ends as Chell is taken to the surface and, after a brief interlude,<sup class="reference" id="cite_ref-pcgamer_wolpaw_interview_39-0" style="line-height:1em;">[40] exits into a wheat field from a corrugated metal shed. The charred and battered Weighted Companion Cube (supposedly incinerated during the events of Portal) is then flung out the door after her before it slams shut.<sup class="reference" id="cite_ref-pcgamer_wolpaw_interview_39-1" style="line-height:1em;">[40] <sup class="reference" id="cite_ref-rpsspoilerinterview_40-0" style="line-height:1em;">[41] In the epilogue, Wheatley floats helplessly through space and expresses regrets about betraying Chell.<sup class="reference" id="cite_ref-tpwhky_37-2" style="line-height:1em;">[38] <sup class="reference" id="cite_ref-pcgamer_wolpaw_interview_39-2" style="line-height:1em;">[40]

[edit] Co-operative campaign
<p style="line-height:19px;color:rgb(0,0,0);font-family:sans-serif;text-align:-webkit-auto;">The co-operative story takes place after the single-player campaign and has some ties into it, but players do not necessarily need to play them in that order.<sup class="reference" id="cite_ref-41" style="line-height:1em;">[42] Player characters Atlas and P-Body are bipedal robots, each with a fully functioning portal gun, who navigate five sets of test chambers together. The robots are introduced in the singleplayer campaign as replacements for GLaDOS's human test subjects. After completing a test chamber, the robots are disassembled and reassembled at the next chamber. After completing each set of chambers, they are returned to a central hub. The puzzles in each set of chambers focus on a particular testing element or puzzle-solving technique. In the first four sets, GLaDOS prepares the robots to venture outside of the test systems of Aperture Laboratories to recover data disks. She destroys them and restores their memories to new bodies, similar to what happens when they die from a test chamber hazard. At first, GLaDOS is excited about her non-human test subjects, but later becomes dissatisfied because the two robots can't actually die.<sup class="reference" id="cite_ref-Portal_2_42-0" style="line-height:1em;">[43] At the conclusion of the co-op story, the robots discover and gain entry to "the Vault", where humans are stored in cryostasis.<sup class="reference" id="cite_ref-fastcompany_portal2_34-1" style="line-height:1em;">[35] GLaDOS gleefully congratulates the robots on locating the humans, whom she sees as new test subjects. She then violently disassembles the robots, telling them, "We still have a lot of work to do."<sup class="reference" id="cite_ref-Portal_2_42-1" style="line-height:1em;">[43]

Credits
Portal Wikipedia: http://en.wikipedia.org/wiki/Portal_(video_game) 

Portal 2 Wikipedia: http://en.wikipedia.org/wiki/Portal_2

The Unofficial Portal Wiki: http://theportalwiki.com/wiki/Main_Page 

Half-Life Wikia: http://half-life.wikia.com/wiki/Main_Page

All information, citation, and reference can be found on these Wiki's.