Portal

***Portal*** is a 2007 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 and Xbox 360 on October 9, 2007, and for the PlayStation 3 on December 11, 2007.[6][7][8] The Windows version of the game is available for download separately through Valve's content delivery system Steam and was released as a standalone retail product on April 9, 2008.[2][3] 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. An OS X version was released as part of the Mac-compatible Steam platform on May 12, 2010.[9] A Linux version was released on Steam as a beta on May 2, 2013,[10] and came out of beta on June 24, 2013.[11] An Android port for the Nvidia Shield was released on May 12, 2014.

The game primarily comprises a series of puzzles that must be solved by teleporting
 the player's character and simple objects using "the Aperture Science
Handheld Portal Device", a device that can create inter-spatial portals 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]

## Gameplay

In *Portal*, the player controls the protagonist, Chell, from a first-person perspective
 as she is challenged to navigate through a series of rooms using the
Aperture Science Handheld Portal Device, or portal gun, under the
watchful supervision of the artificial intelligence GLaDOS.
 The portal gun can create two distinct portal ends, orange and blue.
The portals create a visual and physical connection between two
different locations in three-dimensional space.
 Neither end is specifically an entrance or exit; all objects that
travel through one portal will exit through the other. An important
aspect of the game's physics is momentum redirection.[13]
 As moving objects pass through portals, they come through the exit
portal at the same direction that the exit portal is facing and with the
 same speed with which they passed through the entrance portal.[14]
 For example, a common maneuver is to jump down to a portal on the floor
 and emerge through a wall, flying over a gap or another obstacle. This
allows the player to launch objects or Chell over great distances, both
vertically and horizontally, referred to as 'flinging' by Valve.[13]
 As GLaDOS puts it, "In layman's terms: speedy thing goes in, speedy
thing comes out." If portal ends are not on parallel planes, the
character passing through is reoriented to be upright with respect to
gravity after leaving a portal end.
Chell and all other objects in the game that can fit into the portal
ends will pass through the portal. However, a portal shot cannot pass
through an open portal; it will simply deactivate or create a new portal
 in an offset position. Creating a portal end instantly deactivates an
existing portal end of the same color. Moving objects, glass, special
wall surfaces, liquids, or areas that are too small will not be able to
anchor portals. Chell is sometimes provided with cubes that she can pick
 up and use to climb on or to hold down large buttons that open doors or
 activate mechanisms. Particle fields known as emancipation grills,
occasionally called "fizzlers" in the developer commentary, exist at the
 end of all and within some test chambers; when passed through, they
will deactivate any active portals and disintegrate any object carried
through. The fields also block attempts to fire portals through them.[15]

Although Chell is equipped with mechanized heel springs to prevent damage from falling,[13]
 she can be killed by various other hazards in the test chambers, such
as turret guns, bouncing balls of energy, and toxic liquid. She can also
 be killed by objects falling through portals, and by a series of
crushers that appear in certain levels. Unlike most action games at the
time, there is no health
 indicator; Chell dies if she is dealt a certain amount of damage in a
short time period, but returns to full health fairly quickly. Some
obstacles, such as the energy balls and crushing pistons, deal fatal
damage with a single blow.

GameSpot noted, in its initial review of *Portal*,
 that many solutions exist for completing each puzzle, and that the
gameplay "gets even crazier, and the diagrams shown in the trailer
showed some incredibly crazy things that you can attempt."[16]
 Two additional modes are unlocked upon the completion of the game that
challenge the player to work out alternative methods of solving each
test chamber. Challenge maps are unlocked near the halfway point and
Advanced Chambers are unlocked when the game is completed.[17]
 In Challenge mode, levels are revisited with the added goal of
completing the test chamber either with as little time, with the least
number of portals, or with the fewest footsteps possible. In Advanced
mode, certain levels are made more complex with the addition of more
obstacles and hazards.[18][19]

## Synopsis

### 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 artificial. 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]

### Setting

*Portal* takes place in the Aperture Science Laboratories computer aided enrichment center—Aperture
 Science in short—which is a 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 1943 for the sole purpose of making shower curtains
 for the U.S. military. However, after becoming mentally unstable from
"moon rock poisoning" in 1978, Johnson created a three-tier research 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 terminally ill children's parents to
adults who are in need of dreams), 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.[24] Roughly thirteen years later, work on GLaDOS was completed and the untested AI was activated during the company's first ever bring-your-daughter-to-work day in May 2000.[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, chronologically taking place between *Half-Life* and *Half-Life 2*, occurred during *Portal*‍ '​s events.[25]
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.[26] Aperture Science exists in the *Half-Life* universe. During its development, *Half-Life 2: Episode Two* featured a chapter set on Aperture Science's icebreaker ship *Borealis*, but this was abandoned and removed before release.[27]

### Plot

*Portal*‍ '​s plot is revealed to the player via audio messages
from GLaDOS and visual elements inside rooms found in 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.[13] Chell is promised cake and grief counseling as her reward if she manages to complete all the test chambers.[28]

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.[26]
 Some of the later chambers include automated turrets with childlike
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").[29][30]

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.[31]
 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.[13]

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 and threaten 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 her. 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"[24][32]

The final scene, after a long and speedy zoom through the bowels of the facility, shows a Black Forest cake,[33]
 and the Weighted Companion Cube, surrounded by a mix of shelves
containing dozens of apparently inactive personality cores. One by one a
 number of the cores begin to light up, before a robotic arm descends
and extinguishes the candle on the cake, plunging the room into
darkness.[34] As the credits roll, GLaDOS delivers a concluding report: the song "Still Alive", which declares the experiment to be a huge success, as well as serving to indicate to the player that GLaDOS is still alive.[35]

## Development

### Concept

*Portal* is Valve's spiritual successor to the freeware game *Narbacular Drop*, the 2005 independent game released by students of the DigiPen Institute of Technology; the original *Narbacular Drop* team is now employed at Valve.[36][37] Valve became interested in *Narbacular Drop*
 after seeing the game at DigiPen's annual career fair; Robin Walker,
one of Valve's developers, saw the game at the fair and later contacted
the team providing them with advice and offering to show their game at
Valve's offices. After their presentation, Valve's president Gabe Newell quickly offered the entire team jobs at Valve to develop the game further.[38]
 Newell later commented that he was impressed with the DigiPen team as
"they had actually carried the concept through", already having included
 the interaction between portals and physics, completing most of the
work that Valve would have had to commit on their own.[38] Certain elements have been retained from *Narbacular Drop*,
 such as the system of identifying the two unique portal endpoints with
the colors orange and blue. A key difference in the signature portal
mechanic between the two games however is that *Portal*‍ '​s portal gun cannot create a portal through an existing portal unlike in *Narbacular Drop*. The game's original setting, of a princess trying to escape a dungeon, was dropped in favor of the Aperture Science approach.[38] *Portal* took approximately two years and four months to complete after the DigiPen team was brought into Valve,[39] and no more than ten people were involved with its development.[40] *Portal* writer Erik Wolpaw, who, along with fellow writer Chet Faliszek, was hired by Valve for the game, claimed that "Without the constraints, *Portal* would not be as good a game".[41]

The *Portal* team worked with *Half-Life* series writer Marc Laidlaw on fitting the game into the series' plot.[42] This was done, in part, due to the limited art capabilities of the small team; instead of creating new assets for *Portal*, they decided to tie the game to an existing franchise—*Half-Life*—to allow them to reuse the *Half-Life 2* art assets.[24] Wolpaw and Faliszek were put to work on the dialogue for *Portal*.[37]
 The concept of a computer AI guiding the player through experimental
facilities to test the portal gun was arrived at early in the writing
process.[24]
 They drafted early lines for the yet-named "polite" AI with humorous
situations, such as requesting the player's character to "assume the
party escort submission position", and found this style of approach to
be well-suited to the game they wanted to create, ultimately leading to
the creation of the GLaDOS character.[24]
 GLaDOS was central to the plot, as Wolpaw notes "We designed the game
to have a very clear beginning, middle, and end, and we wanted GLaDOS to
 go through a personality shift at each of these points."[43] Wolpaw further describes the idea of using cake as the reward came about as "at the beginning of the *Portal*
 development process, we sat down as a group to decide what philosopher
or school of philosophy our game would be based on. That was followed by
 about 15 minutes of silence and then someone mentioned that a lot of
people like cake."[24][43] The cake element along with additional messages given to the player in the behind-the-scenes areas were written and drawn by Kim Swift.[44]

### Design

The austere settings in the game came about because testers spent too
 much time trying to complete the puzzles using decorative but
non-functional elements. As a result, the setting was minimized to make
the usable aspects of the puzzle easier to spot, using the clinical feel
 of the setting in the film *The Island* as reference.[45]
 While there were plans for a third area, an office space, to be
included after the test chambers and the maintenance areas, the team ran
 out of time to include it.[45]
 They also dropped the introduction of the Rat Man, a character who left
 the messages in the maintenance areas, to avoid creating too much
narrative for the game,[46] though the character was developed further in a tie-in comic "Lab Rat", that ties *Portal* and *Portal 2*‍ '​s story together.[20][21]
 According to project lead Kim Swift, the final battle with GLaDOS went
through many iterations, including having the player chased by James Bond lasers, which was partially applied to the turrets, Portal Kombat
 where the player would have needed to redirect rockets while avoiding
turret fire, and a chase sequence following a fleeing GLaDOS.
Eventually, they found that playtesters enjoyed a rather simple puzzle
with a countdown timer near the end; Swift noted, "Time pressure makes
people think something is a lot more complicated than it really is", and
 Wolpaw admitted, "It was really cheap to make [the neurotoxin gas]" in
order to simplify the dialogue during the battle.[40]
Chell's face and body are modeled after Alésia Glidewell,
 an American freelance actress and voice-over artist, selected by Valve
from a local modeling agency for her face and body structure.[39][47]
 Ellen McLain provided the voice of the antagonist GLaDOS. Erik Wolpaw
noted, "When we were still fishing around for the turret voice, Ellen
did a sultry version. It didn't work for the turrets, but we liked it a
lot, and so a slightly modified version of that became the model for
GLaDOS's final incarnation."[43] Mike Patton performed the growling and snarling voice of GLaDOS's final personality core, named the Anger Sphere.

The Weighted Companion Cube inspiration was from project lead Kim
Swift with additional input from Wolpaw from reading some "declassified
government interrogation thing" whereby "isolation leads subjects to
begin to attach to inanimate objects";[40][43]
 Swift commented, "We had a long level called Box Marathon; we wanted
players to bring this box with them from the beginning to the end. But
people would forget about the box, so we added dialogue, applied the
heart to the cube, and continued to up the ante until people became
attached to the box. Later on, we added the incineration idea. The
artistic expression grew from the gameplay."[45]
 Wolpaw further noted that the need to incinerate the Weighted Companion
 Cube came as a result of the final boss battle design; they recognized
they had not introduced the idea of incineration necessary to complete
the boss battle, and by training the player to do it with the Weighted
Companion Cube, found the narrative "way stronger" with its "death".[48] Swift noted that any similarities to psychological situations in the Milgram experiment or *2001: A Space Odyssey* are happenstance.[45]

The portal gun's full name, Aperture Science Handheld Portal Device,
can be abbreviated as ASHPD, which resembles a shortening of the name
Adrian Shephard, the protagonist of *Half-Life: Opposing Force*. This similarity was noticed by fans before the game's release; as a result, the team placed a red herring in the game by having the letters of Adrian Shephard highlighted on keyboards found within the game.[45]
 According to Kim Swift, the cake is a Black Forest cake that she
thought looked the best at the nearby Regent Bakery and Café in Redmond, Washington, and, as an Easter egg within the game, its recipe is scattered among various screens showing lines of binary code.[33][49] The Regent Bakery has stated that since the release of the game, its Black Forest cake has been one of its more popular items.[49]

### Soundtrack

Most of the game's soundtrack is non-lyrical ambient music composed by Kelly Bailey and Mike Morasky, somewhat dark and mysterious to match the mood of the environments. The closing credits song, "Still Alive", was written by Jonathan Coulton and sung by Ellen McLain (a classically trained operatic soprano)
 as the GLaDOS character. A brief instrumental version of Still Alive is
 played in an uptempo Latin style over radios in-game. Wolpaw notes that
 Coulton was invited to Valve a year before the release of *Portal*,
 though it was not yet clear where Coulton would contribute. "Once Kim
[Swift] and I met with him, it quickly became apparent that he had the
perfect sensibility to write a song for GLaDOS."[35][43] The use of the song over the closing credits was based on a similar concept from the game *God Hand*, one of Wolpaw's favorite titles.[50] The song was released as a free downloadable song for the music video game *Rock Band* on April 1, 2008.[51][52][53] The soundtrack for *Portal* was released as a part of *The Orange Box Original Soundtrack*[54] and includes both GLaDOS's in-game rendition and Coulton's vocal mix of "Still Alive".

*Portal*‍ '​s soundtrack was released as part of a four-disc retail release, *Portal 2: Songs To Test By (Collector's Edition)*, on October 30, 2012, featuring music from both games.[55] The game's soundtrack became available via Steam Music on September 24, 2014.[56]

### Merchandise

The popularity of the game and of its characters has led Valve to develop merchandise for *Portal* made available through its online Steam store. Some of the more popular items were the Weighted Companion Cube plush toys and fuzzy dice.[57] When first released, both were sold out in under 24 hours.[58]
 Other products available through the Valve store include T-shirts and
Aperture Science coffee mugs and parking stickers, and merchandise
relating to the phrase *the cake is a lie*, which has become an internet meme.
 Wolpaw noted they did not expect certain elements of the game to be as
popular as they were, while other elements they had expected to become
fads were ignored, such as a giant hoop that rolls on-screen during the
final scene of the game that the team had named Hoopy.[24]

### Distribution

#### Demo

In January 2008, Valve released a special demo version titled ***Portal: The First Slice***, free for any Steam user using Nvidia graphics hardware as part of a collaboration between the two companies.[59] It also comes packaged with *Half-Life 2: Deathmatch*, *Peggle Extreme*, and *Half-Life 2: Lost Coast*. The demo includes test chambers 00 to 10 (eleven in total). Valve has since made the demo available to all Steam users.[60]

#### *Portal*

*Portal* was first released as part of *The Orange Box* for Microsoft Windows and Xbox 360 on October 9, 2007,[6][7] and for the PlayStation 3 on December 11, 2007.[8] The Windows version of the game is also available for download separately through Valve's content delivery system, Steam,[3] and was released as a standalone retail product on April 9, 2008.[2] In addition to *Portal*, the *Box* also included *Half-Life 2* and its two add-on episodes, as well as *Team Fortress 2*. *Portal*‍ '​s inclusion within the *Box* was considered an experiment by Valve; having no idea of the success of *Portal*, the *Box* provided it a "safety net" via means of these other games. *Portal* was kept to a modest length in case the game did not go over well with players.[34] Since then, a standalone version of the game was released for Microsoft Windows users.

*Portal* was the first Valve-developed game to be added to the
OS X-compatible list of games available on the launch of the Steam
client for Mac on May 12, 2010,[9]
 supporting Steam Play, in which players that had bought the game either
 on a Macintosh or Windows computer could also play it on the alternate
system. As part of the promotion, *Portal* was offered as a free title for any Steam user during the two weeks following the Mac client's launch.[61] Within the first week of this offer, over 1.5 million copies of the game were downloaded through Steam.[62]
 A similar promotion was held in September 2011, near the start of a
traditional school year, encouraging the use of the game as an
educational tool for science and mathematics.[63][64] Valve wrote that they felt that *Portal*
 "makes physics, math, logic, spatial reasoning, probability, and
problem-solving interesting, cool, and fun", a necessary feature to draw
 children into learning.[65] This was tied to Digital Promise,
 a United States Department of Education initiative to help develop new
digital tools for education, and which Valve is part of.[66]

During 2014 GPU Technology Conference on March 25, 2014, Nvidia announced that they are porting *Portal* to their Android handheld, the Nvidia Shield.[67] The version was released on May 12, 2014.[68]

#### *Portal: Still Alive*

*Portal: Still Alive* was announced as an exclusive Xbox Live Arcade game at the 2008 E3 convention, and was released on October 22, 2008.[69] It features the original game, 14 new challenges, and new achievements.[70] The additional content was based on levels from the map pack *Portal: The Flash Version* created by We Create Stuff and contains no additional story-related levels.[71] According to Valve spokesman Doug Lombardi, Microsoft had previously rejected *Portal* on the platform due to its large size.[72] *Portal: Still Alive* was well received by reviewers.[73] 1UP.com's Andrew Hayward stated that, with the easier access and lower cost than paying for *The Orange Box*, *Portal* is now "stronger than ever".[74] IGN
 editor Cam Shea ranked it fifth on his top 10 list of Xbox Live Arcade
games. He stated that it was debatable whether an owner of *The Orange Box*
 should purchase this, as its added levels do not add to the plot.
However, he praised the quality of the new maps included in the game.[75] The game ranked 7th in a later list of top Xbox Box Live titles compiled by IGN's staff in September 2010.[76]

#### Mods

A modding community has developed around *Portal*, with users creating their own test chambers and other in-game modifications.[77][78] The group "We Create Stuff" created an Adobe Flash version of *Portal*, titled *Portal: The Flash Version*, just prior to release of *The Orange Box*. This flash version was well received by the community[79] and the group have since converted it to a map pack for the published game.[80] Another mod, *Portal: Prelude*,
 is an unofficial prequel developed by an independent team of three that
 focuses on the pre-GLaDOS era of Aperture Science, and contains
nineteen additional "crafty and challenging" test chambers.[81][82] An ASCII version of *Portal* was created by Joe Larson.[83][84] An unofficial port of *Portal* to the iPhone using the Unity game engine was created but only consisted of a single room from the game.[85][86] *Mari0* is a fan-made four-player coop mashup of *Portal* and the original *Super Mario Bros.*.[87]

### Sequel

Main article: Portal 2

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 multiplayer next, or *Portal 2*, or release map packs."[18] Some rumors regarding a sequel arose due to casting calls for voice actors.[88][89] On March 10, 2010, *Portal 2* was officially announced for a release late in that year;[90] the announcement was preceded by an alternate reality game based on unexpected patches made to *Portal* that contained cryptic messages in relation to *Portal 2*‍
 '​s announcement, including an update to the game, creating a different
 ending for the fate of Chell. The original game left her in a deserted
car park after destroying GLaDOS, but the update involved Chell being
dragged back into the facility by a "Party Escort Bot". Though *Portal 2* was originally announced for a Q4 2010 release, the game was released on April 19, 2011.[32][91][92][93]

### Film adaptation

In February 2013, it was reported that J. J. Abrams is in talks with Valve to develop a movie based upon *Portal*, alongside an adaptation of *Half-Life*. Both projects are currently in the early states of development with no production date yet confirmed.[94]

## Critical reception

See also: Critical reception of The Orange Box

 GameRankings
 Publication
 1UP.com
 GameSpy

*Portal* received critical acclaim, often earning more praise than either *Half-Life 2: Episode Two* or *Team Fortress 2*, two titles also included in *The Orange Box*. It was praised for its unique gameplay and dark, deadpan humor.[97] Eurogamer cited that "the way the game progresses from being a simple set of perfunctory tasks to a full-on part of the *Half-Life* story is absolute genius",[98] while GameSpy noted that "What *Portal* lacks in length, it more than makes up for in exhilaration."[99] The game was criticized for sparse environments, and both criticized and praised for its short length.[100] Aggregate reviews for the stand-alone PC version of *Portal* gave the game an average rating of 89% based on 27 reviews through Game Rankings,[95] and 90% through 28 reviews on Metacritic.[96] Upon release of *Portal 2*, Valve stated that *Portal* has sold more than four million copies through the retail versions, including the standalone game and *The Orange Box*,
 and from the Xbox Live Arcade version. This figure does not include
sales figures for Valve's own Steam digital download service.[101]

The game generated a fan following for the Weighted Companion Cube[102]—even though the cube itself does not talk or act in the game. Fans have created plush[103] and papercraft versions of the cube and the various turrets,[104] as well as PC case mods[105] and models of the Portal cake and portal gun.[106][107][108] Jeep Barnett, a programmer for *Portal*,
 noted that players have told Valve that they had found it more
emotional to incinerate the Weighted Companion Cube than to harm one of
the "Little Sisters" from *BioShock*.[45]
 Both GLaDOS and the Weighted Companion Cube were nominated for the Best
 New Character Award on G4, with GLaDOS winning the award for "having
lines that will be quoted by gamers for years to come."[109][110][111]

Ben "Yahtzee" Croshaw of Zero Punctuation
 gave the game the only entirely positive review in the show's history,
calling it "the most fun you'll have with your PC until they invent a
force-feedback codpiece". Croshaw went on to say: "I went in expecting a
 slew of interesting portal-based puzzles and that's exactly what I got,
 but what I wasn't expecting was some of the funniest pitch black humor
I've ever heard in a game". He states that, while the game was short,
the two- to three-hour length of the game was perfect as the game did
not outstay its welcome, and called the ending "balls-tighteningly
fantastic", while praising the game as "absolutely sublime from start to
 finish" (adding that he would jam forks in his eyes if he ever praised a
 game so highly again).[112]

*Portal*‍ '​s story has been stated to be well-established in the context of Erving Goffman's dissemination on dramaturgy, *The Presentation of Self in Everyday Life*, which equates one's persona to the front and back stage areas of a theater. In the case of *Portal*,
 the story carefully establishes the front stage, the pretense of the
Enrichment Center, and hints at problems in the back stage through
various technical faults, and then slowly reveals more and more of the
back stage to the player throughout the game.[113]
 Due to this, the video game was made part of the required course
material among other classical and contemporary works, including
Goffman's work, for a freshman course "devoted to engaging students with
 fundamental questions of humanity from multiple perspectives and
fostering a sense of community" for Wabash College in 2010.[114][115] *Portal* has also been cited as a strong example of instructional scaffolding
 that can be adapted for more academic learning situations, as the
player, through careful design of levels by Valve, is first hand-held in
 solving simple puzzles with many hints at the correct solution, but
this support is slowly removed as the player progresses in the game, and
 completely removed when the player reaches the second half of the game.[116] Rock, Paper, Shotgun's Hamish Todd considered *Portal*
 as an exemplary means of game design by demonstrating a series of
chambers after the player has obtained the portal gun that gently
introduce the concept of flinging without any explicit instructions.[117] *Portal* was exhibited at the Smithsonian Art Exhibition in America from February 14 through September 30, 2012. *Portal* won the "Action" section for the platform "Modern Windows".[118]

### Awards

*Portal* has won several awards:

* At the 2008 Game Developers Choice Awards, *Portal* won Game of the Year, along with the Innovation Award and Best Game Design.[119]
* IGN honored *Portal* with several awards, for Best Puzzle Game for PC[120] and Xbox 360,[121] Most Innovative Design for PC,[122] and Best End Credit Song (for "Still Alive") for Xbox 360,[123] along with overall honors for Best Puzzle Game[124] and Most Innovative Design.[125]
* In its Best of 2007, GameSpot honored *The Orange Box* with 4 awards in recognition of *Portal*, giving out honors for Best Puzzle Game,[126] Best New Character(s) (for GLaDOS),[127] Funniest Game,[128] and Best Original Game Mechanic (for the portal gun).[129]
* *Portal* was awarded Game of the Year (PC), Best Narrative

(PC), and Best Innovation (PC and console) honors by 1UP.com in its 2007
 editorial awards.[130]

* GamePro honored the game for Most Memorable Villain (for GLaDOS) in its Editors' Choice 2007 Awards.[131]
* *Portal* was awarded the Game of the Year award in 2007 by Joystiq,[132] Good Game,[133] and Shacknews.[134]
* The Most Original Game award by *X-Play*.[135]
* In *Official Xbox Magazine*‍ '​s 2007 Game of the Year Awards, *Portal* won Best New Character (for GLaDOS), Best Original Song (for "Still Alive"), and Innovation of the Year.[136]
* In GameSpy's 2007 Game of the Year awards, *Portal* was recognized as Best Puzzle Game,[137] Best Character (for GLaDOS), and Best Sidekick (for the Weighted Companion Cube).[137]
* The A.V. Club called it the Best Game of 2007.[138]
* The webcomic *Penny Arcade* awarded *Portal* Best Soundtrack, Best Writing, and Best New Game Mechanic in its satirical 2007 We're Right Awards.[139]
* Eurogamer gave *Portal* first place in its Top 50 Games of 2007 rankings.[140]
* IGN also placed GLaDOS, (from *Portal*) as the #1 Video Game Villain on its Top-100 Villains List.[141]
* GamesRadar named it the best game of all time.[142]
* In November 2012, *Time* named it one of the 100 greatest video games of all time.[143]
* *Wired* considered *Portal* to be one of the most influential games of the first decade of the 21st century, believing it to be the prime example of quality over quantity for video games.[144]