Half Life 2

Half-Life 2 (stylized as HλLF-LIFE2 or simply as λ2), the sequel to Half-Life, is a first-person shooter video game and a signature title in the Half-Life series. Developed by Valve Corporation, it was initially released on November 16, 2004, following a protracted five-year, $40 million development cycle, during which a substantial part of the project was leaked and distributed on the Internet.

The game was developed alongside Valve's Steam software. It introduced the Source game engine and, because of Steam, is the first video game to require online product activation. 

Like its predecessor, Half-Life 2 was met with near-unanimous critical acclaim.  It was praised for its advanced physics, animation, sound, AI, graphics, and narrative. The game won 39 "Game of the Year" awards, and a couple of publications have named it "Game of the Decade". Over 6.5 million copies of Half-Life 2 were sold at retail by December 3, 2008, making it a bestselling PC game (not including the number of sales via Steam). As of February 9, 2011, Half-Life 2 has sold over 12 million copies.

Gameplay
Half-Life 2, like its predecessor Half-Life, is a singleplayer first-person shooter broken into chapters, permanently casting the player as Gordon Freeman. The sequel has nearly the same mechanics as Half-Life, including health-and-weapon systems and periodic puzzles. The player also starts without items, slowly building up an arsenal over the course of the game. Despite the game's mainly linear nature, much effort was put into making exploration rewarding and interesting; many optional areas can be missed or avoided.

A diverse set of enemies are present with different tactics: some coordinate in groups, some fly, some use predictable but powerful attacks, some are armed, some utilize melee and/or swift movement, and some rely on lurking and/or obscurity. Gordon can kill enemies directly with his weapons, or indirectly using environmental hazards such as explosive barrels and gas fires. At one point in the game, Gordon can be joined by up to four Resistance soldiers, and can send his team further from him or call them back; however, they can still die easily. Squad members are indicated on the HUD (squad member icons with a cross sign are field medics).

Many of the game's new features utilize its detailed physics simulation. Two sections of the game involve driving vehicles. Instead of button-based puzzles from Half-Life, environmental puzzles are also introduced with makeshift mechanical systems, revolving around the player's new ability to pick up, move, and place objects. Solutions involve objects' physical properties, such as shape, weight, and buoyancy. For example, in Chapter 3: Route Kanal, the player is required to stack cinder blocks on a makeshift see-saw ramp to proceed.

Part-way through the game, Gordon acquires the Gravity Gun, which allows him to manipulate objects of various sizes (e.g. pulling a crate from a distance and later firing it away. These abilities are required to solve some puzzles later in the game, and can also be used in combat.

The game does not contain pre-rendered or scripted cutscenes; the story proceeds via exposition from other characters, as well as events that unfold in the game world.

Background and Setting
Half-Life 2 is a work of science fiction presenting a dystopian alternate history of Earth, where the resources of the planet, including the human race itself, are being harvested by an oppressive multidimensional empire, known as the Combine. The game is set around the fictitious City 17, somewhere in Eastern Europe, roughly 20 years after the events of Half-Life. During Half-Life, the scientists at the game's Black Mesa Research Facility cause an interdimensional instability, known in the series as a resonance cascade, which Gordon tries to resolve. However, by killing the overlord of the attacking "border-world", Xen, Gordon unwittingly widens the dimensional rift, which leads to disasters on Earth. This became known as the "Black Mesa Incident".

Some time after the ending of Half-Life, this instability attracts the attention of the Combine, and they invade. Humanity surrenders at the conclusion of the resulting Seven Hour War. City 17 becomes the home of the gigantic Combine Citadel, and Dr. Wallace Breen, who had managed "the Earth's...surrender," is appointed representative and Administrator to supervise the survivors on behalf of the Combine. Unable to breed due to the Combine suppression field, humanity matures (i.e. no children remain, as seen in the first chapter). The Combine implements a brutal police state of Civil Protection officers and Overwatch soldiers, and the underground Lambda Resistance forms.

Plot
The game begins as Gordon Freeman is brought out of stasis by the mysterious G-Man, who "inserts" him into a train nearing its destination: City 17 (Point Insertion). After arriving at the station and eluding Combine forces, Gordon joins the Lambda Resistance, organized by fellow friends from Black Mesa, including Barney Calhoun, who is working undercover as a Combine CP officer; and Alyx Vance, the daughter of one of Gordon's former colleagues, Dr. Eli Vance. After a failed attempt to teleport Gordon to Black Mesa East from Dr. Kleiner's makeshift laboratory ("A Red Letter Day"), Gordon, who is re-equipped with the HEV suit and a crowbar, is forced to embark on foot through the city's old canal system (Route Kanal). After obtaining an airboat (Water Hazard), he eventually reaches Black Mesa East, several miles from the city. Gordon is reintroduced to Eli <sup class="reference" id="cite_ref-blackmesaeast1_22-0">, and meets Dr. Judith Mossman. Alyx, who is glad to see him, introduces Gordon to D0g, her car-sized pet robot, and gives him the Gravity Gun. Later, Black Mesa East comes under Combine attack, and Eli and Mossman are captured and taken to the Combine prison Nova Prospekt. Gordon and Alyx are forced to take separate ways to Nova Prospekt; Gordon is to detour through the headcrab zombie-infested town of Ravenholm, with the help of its last survivor, Father Grigori ("We Don't Go To Ravenholm..."). After venturing through a mine and combating snipers, Gordon makes his way with a Tau cannon-rigged dune buggy along Highway 17, a crumbling coastal road. He eventually helps one of the resistance leaders, Colonel Odessa Cubbage, defend resistance points at New Little Odessa, and Lighthouse Point from an impending Combine assault.

After traveling past Lighthouse Point and crossing an antlion-infested beach (Sandtraps), Gordon storms Nova Prospekt where he is reunited with Alyx <sup class="reference" id="cite_ref-hl2guideIX_23-0"> They manage to locate Eli, and discover that Mossman is a Combine informant (Entanglement). Before they can stop her, she teleports herself and Eli back to City 17's Citadel. The Combine teleporter explodes as Gordon and Alyx use it to escape Nova Prospekt.

Rematerializing in Kleiner's lab, Gordon and Alyx learn that they were caught in what a shaken Dr. Kleiner calls "a very slow teleport," during which a week's time had passed.<sup class="reference" id="cite_ref-goneforaweek_24-0"> During their absence, the Resistance, who heard about what had happened at Nova Prospekt, has mobilized against the Combine, turning City 17 into a warzone.<sup class="reference" id="cite_ref-hl2guideX_25-0"> During the battle, Alyx is captured by the Combine and taken to the Citadel (Anticitizen One).<sup class="reference" id="cite_ref-hl2guideXI_26-0">

After numerous battles across the city, a final bit of help from Dog and Barney ("Follow Freeman!"),<sup class="reference" id="cite_ref-followfreeman.21_last_27-0"> Gordon enters the Citadel to rescue Alyx and Eli. However, he is caught in a Combine Confiscation Field chamber that destroys all of his weapons except for the Gravity Gun; instead, the energy "backfires" and enhances the Gravity Gun's capabilities, allowing Gordon to escape and dispatch platoons of Citadel soldiers with ease (Our Benefactors). Eventually, Gordon is captured riding in a Combine transport pod and is taken to Dr. Breen's office, where he and Dr. Mossman are waiting with Eli and Alyx in captivity (Dark Energy). Dr. Breen begins to explain his plans for further conquest of the humans by the Combine, contrary to what he told Dr. Mossman.<sup class="Template-Fact" style="white-space:nowrap;"> Angered, Dr. Mossman frees Gordon, Alyx, and Eli before they are beamed off-world. Dr. Breen tries to escape through a Dark Energy portal, but Gordon pursues him and destroys the reactor with the supercharged Gravity Gun.<sup class="reference" id="cite_ref-hl2guideXIV_28-0"> Breen appears to be annihilated in the resulting explosion. Just before Gordon and Alyx are about to meet a similar fate, time suddenly stops. The G-Man reappears, and praises Gordon for his actions on the job before putting him back into stasis, apparently leaving Alyx to face the explosion alone.

Development
For Half-Life 2, Valve Corporation developed a new game engine called the Source engine, which handles the game's visual, audio, and artificial intelligence elements. The Source engine comes packaged with a heavily modified version of the Havok physics engine that allows for an extra dimension of interactivity in both single-player and online environments.<sup class="reference" id="cite_ref-30"> The engine can be easily upgraded because it is separated in modules. When coupled with Steam, it becomes easy to roll out new features. One such example is high dynamic range rendering, which Valve first demonstrated in a free downloadable level called Lost Coast for owners of Half-Life 2.<sup class="reference" id="cite_ref-31"> HDR is now part of all Valve games. Several other games use the Source engine, including Day of Defeat: Source and Counter-Strike: Source, both of which were also developed by Valve.<sup class="reference" id="cite_ref-32">

Integral to Half-Life 2 on both the Windows and Mac platforms is the Steam content delivery system developed by Valve Corporation. All Half-Life 2 players on PC are required to have Steam installed and a valid account in order to play.<sup class="reference" id="cite_ref-33"> Steam allows customers to purchase games and other software straight from the developer and have them downloaded directly to their computer as well as receiving "micro updates." These updates also make hacking the game harder to do and has thus far been somewhat successful in staving off cheats and playability for users with unauthorized copies.<sup class="reference" id="cite_ref-34"> Steam can also be used for finding and playing multiplayer games through an integrated server browser and friends list, and game data can be backed up with a standard CD or DVD burner. Steam and a customer's purchased content can be downloaded onto any computer, as long as that account is only logged in at one location at a given time. The usage of Steam has not gone without controversy.<sup class="reference" id="cite_ref-35"> Some users have reported numerous problems with Steam, sometimes being serious enough to prevent a reviewer from recommending a given title available on the service. In other cases, review scores have been lowered.<sup class="reference" id="cite_ref-36">

The book, Half-Life 2: Raising the Bar, revealed many of the game's original settings and action that were cut down or removed from the game. Half-Life 2 was originally intended to be a darker game with grittier artwork, where the Combine were more obviously draining the oceans for minerals and replacing the atmosphere with noxious, murky gases. Nova Prospekt was originally intended to be a small Combine rail depot built on an old prison in the wasteland. Eventually, Nova Prospekt grew from a stopping-off point along the way to the destination itself.<sup class="reference" id="cite_ref-raisebar_37-0">

Leak
Half-Life 2 was merely a rumor until a strong impression at E3 in May 2003, where it won several awards for best in show. It had a release date of September 2003, but was delayed. This pushing back of HL2's release date came in the wake of the cracking of Valve's internal network<sup class="reference" id="cite_ref-leak_delays_release_38-0"> through a null session connection to Tangis which was hosted in Valve's network and a subsequent upload of an ASP shell, resulting in the leak of the game's source code and many other files including maps, models and a playable early version of Half-Life Source and Counter-Strike Source in early September 2003.<sup class="reference" id="cite_ref-source_code_leak_39-0"> On October 2, 2003, Valve CEO Gabe Newell publicly explained in the Halflife2.net (now ValveTime.net) forums<sup class="reference" id="cite_ref-40"> the events that Valve experienced around the time of the leak, and requested users to track down the perpetrators if possible.

In June 2004, Valve Software announced in a press release that the FBI had arrested several people suspected of involvement in the source code leak.<sup class="reference" id="cite_ref-axel_g_arrest_41-0"> Valve claimed the game had been leaked by a German black-hat hacker named Axel "Ago" Gembe. After the leak, Gembe had contacted Newell through e-mail (also providing an unreleased document planning the E3 events). Newell kept corresponding with Gembe, and Gembe was led into believing that Valve wanted to employ him as an in-house security auditor. He was to be offered a flight to the USA and was to be arrested on arrival by the FBI. When the German government became aware of the plan, Gembe was arrested in Germany instead, and put on trial for the leak as well as other computer crimes in November 2006, such as the creation of Agobot, a highly successful trojan which harvested users' data.<sup class="reference" id="cite_ref-42"> <sup class="reference" id="cite_ref-44">

At the trial in November 2006 in Germany, Gembe was sentenced to two years' probation. In imposing the sentence, the judge took into account such factors as Gembe's difficult childhood and the fact that he was taking steps to improve his situation.

Ports and Updates
On December 22, 2005, Valve released a 64-bit version of the Source game engine that theoretically takes advantage of x86-64 processor-based systems running Windows XP Professional x64 Edition, Windows Server 2003 x64, Windows Vista x64, or Windows Server 2008 x64. This update, delivered via Steam, enabled Half-Life 2 and other Source-based games to run natively on 64 bit processors, bypassing the 32-bit compatibility layer. Gabe Newell, one of the founders of Valve, stated that this is "an important step in the evolution of our game content and tools," and that the game benefits greatly from the update.<sup class="reference" id="cite_ref-amd64_46-0"> The response to the release varied: some users reported huge performance boosts, while technology site Techgage found several stability issues and no notable frame rate improvement.<sup class="reference" id="cite_ref-techgage_47-0"> At the time of release, 64-bit users reported bizarre in-game errors including characters dropping dead, game script files not being pre-cached (i.e., loaded when first requested instead), map rules being bent by AI, and other glitches.<sup class="reference" id="cite_ref-64-bit_problems_48-0">

An Xbox port published by Electronic Arts was released on November 15, 2005. While subject to positive reception, critics cited its lack of multiplayer and frame-rate issues as problems, and the game received somewhat lower scores than its PC counterpart.<sup class="reference" id="cite_ref-xbox_reviews_49-0">

During Electronic Arts summer press event on July 13, 2006, Gabe Newell, cofounder of Valve Corporation, announced that Half-Life 2 would ship on next-generation consoles (specifically, the Xbox 360 and PlayStation 3) along with episodes One and Two, Team Fortress 2, and Portal<sup class="reference" id="cite_ref-nextgenconfirmation_50-0"> in a package called The Orange Box. The Windows version was released on October 10, 2007 as both a retail boxed copy, and as a download available through Valve's Steam service. The Xbox 360 version was also released on October 10, 2007. A PlayStation 3 version was released on December 11, 2007.<sup class="reference" id="cite_ref-51">

On May 26, 2010, Half-Life 2, along with episodes One and Two, was released for Mac OS X.<sup class="reference" id="cite_ref-osx_announce_52-0"> Portal was made available for the platform on May 13, 2010, and Mac support for Team Fortress 2 was added on June 10, 2010, completing the The Orange Box package.<sup class="reference" id="cite_ref-tf2_osx_release_53-0"> Valve began selling The Orange Box for Mac OS X on May 26, 2010, despite the notable absence of Team Fortress for about a month.

Soundtrack
Purchasers of the Gold Package of the game were given (among other things) a CD soundtrack, titled The Soundtrack of Half-Life 2, containing nearly all the music from the game, along with three bonus tracks. This CD was available for separate purchase via the Valve online store.

Tracks 15, 16, 18 and 42 are bonus tracks that are exclusive to the CD soundtrack. Tracks 44 to 51 are tracks from the game that did not appear on the soundtrack CD. Many of the tracks were retitled and carried over from the Half-Life soundtrack; The names in parentheses are the original titles. Tracks 34, 41, and 42 are remixes. All listed tracks were composed by Kelly Bailey.

Distribution
A 1 GB portion of Half-Life 2 became available for pre-load through Steam on August 26, 2004. This meant that customers could begin to download encrypted game files to their computer before the game was released. When the game's release date arrived, customers were able to pay for the game through Steam, unlock the files on their hard drives and play the game immediately, without having to wait for the whole game to download. The pre-load period lasted for several weeks, with several subsequent portions of the game being made available, to ensure all customers had a chance to download the content before the game was released.<sup class="reference" id="cite_ref-54">

Half-Life 2 was simultaneously released through Steam, CD, and on DVD in several editions. Through Steam, Half-Life 2 had three packages that a customer could order. The basic version ("Bronze") includes only Half-Life 2 and Counter-Strike: Source, whereas the "Silver" and "Gold" (collector's edition) versions also include Half-Life: Source (ports of the original Half-Life and Day of Defeat mod to the new engine). The collector's edition/Gold version additionally includes merchandise such as a T-shirt, a strategy guide, and a CD containing the soundtrack used in Half-Life 2. Both the disc and Steam version require Steam to be installed and active for play.<sup class="reference" id="cite_ref-55">

A demo version with the file size of a single CD was later made available in December 2004 at the web site of graphics card manufacturer ATI Technologies, who teamed up with Valve for the game. The demo contains part of the opening level of the game, and also part of the chapter "We Don't Go To Ravenholm." In September 2005, Electronic Arts distributed the Game of the Year edition of Half-Life 2. Compared to the original CD-release of Half-Life 2, the GOTY edition adds Half-Life: Source.

Critical Reception
Half-Life 2's public reception was overwhelmingly positive in terms of reviews, acclaim and sales. Forbes reported on February 9, 2011 that the game has sold 12 million copies.<sup class="reference" id="cite_ref-75"> It received an aggregated score of 96% on both GameRankings and Metacritic.<sup class="reference" id="cite_ref-autogenerated1_14-1"> <sup class="reference" id="cite_ref-metacriticreview_64-1"> Sources such as GameSpy,<sup class="reference" id="cite_ref-gamespyreview_69-1"> The Cincinnati Enquirer,<sup class="reference" id="cite_ref-cincin_73-1"> and The New York Times<sup class="reference" id="cite_ref-nytreview_74-1"> have given perfect reviewing scores, and others such as PC Gamer<sup class="reference" id="cite_ref-pcgamerreview_72-1"> and IGN<sup class="reference" id="cite_ref-ignreview_70-1"> gave near-perfect scores, while the game became the fifth title to receive Edge magazine's ten-out-of-ten score.<sup class="reference" id="cite_ref-edgereview_66-1"> Critics who applauded the game cited the advanced graphics and physics.<sup class="reference" id="cite_ref-gameproreview_67-1"> <sup class="reference" id="cite_ref-nytreview_74-2"> Maximum PC awarded Half-Life 2 an unprecedented 11 on their rating scale which normally peaks at 10, and named it the "best game ever made".<sup class="reference" id="cite_ref-maximumpcreview_71-1">

In a review of The Orange Box, IGN stated that although Half Life 2 has already been released through other mediums, the game itself is still enjoyable on a console. They also noted that the physics of Half-Life 2 are very impressive despite being a console title. However, it was noted that the graphics on the Xbox 360 version of Half-Life 2 were not as impressive as when the title was released on the PC.<sup class="reference" id="cite_ref-76"> GameSpot's review of The Orange Box noticed that the content of both the Xbox 360 releases, and PlayStation 3 releases were exactly alike, the only issue with the PS3 version was that it had noticeable frame-rate hiccups. GameSpot continued to say that the frame rates issues were only minor but some consider them to be a significant irritation.<sup class="reference" id="cite_ref-gamespotreview_68-1">

Several critics, including some that had given positive reviews, complained about the required usage of the program Steam, the requirement to create an account, register the products, and permanently lock them to the account before being allowed to play, along with installation difficulties and lack of support.<sup class="reference" id="cite_ref-nytreview_74-3">

Awards
Half-Life 2 earned 39 Game of the Year awards,<sup class="reference" id="cite_ref-valve_10-1"> including Overall Game of the Year at IGN, GameSpot's Award for Best Shooter, GameSpot's Reader's Choice — PC Game of the Year Award, Game of the Year from The Academy of Interactive Arts & Sciences, and "Best Game" with the Game Developers Choice Awards, where it was also given various awards for technology, characters, and writing. Edge magazine awarded Half Life 2 with its top honor of the year with the award for Best Game, as well as awards for Innovation and Visual Design. The game also had a strong showing at the 2004 British Academy Video Games Awards, picking up six awards, more than any other game that night, with awards including "Best Game" and "Best Online and Multiplayer."<sup class="reference" id="cite_ref-BBC_77-0">

Guinness World Records awarded Half-Life 2 the world record for "Highest Rated Shooter by PC Gamer Magazine" in the Guinness World Records: Gamer's Edition 2008. Other records awarded the game in the book include, "Largest Digital Distribution Channel" for Valve's Steam service, "First Game to Feature a Gravity Gun", and "First PC Game to Feature Developer Commentary".<sup class="reference" id="cite_ref-78"> In 2009, Game Informer put Half-Life 2 5th on their list of "The Top 200 Games of All Time", saying that "With Half-Life 2, Valve redefined the way first-person shooters were created".<sup class="reference" id="cite_ref-gi_best_79-0">

Half-Life 2 was selected by readers of The Guardian as the best game of the decade, with praise given especially to the environment design throughout the game. According to the newspaper, it "pushed the envelope for the genre, and set a new high watermark for FPS narrative". One author commented: "Half Life 2 always felt like the European arthouse answer to the Hollywood bluster of Halo and Call of Duty".<sup class="reference" id="cite_ref-guardian1_11-1">

Half-Life 2 won Crispy Gamer's 'Game of the Decade'<sup class="reference" id="cite_ref-crispygamer1_12-1"> tournament style poll. It also won Reviews on the Run's<sup class="reference" id="cite_ref-reviewsontherun1_13-1"> and IGN's<sup class="reference" id="cite_ref-autogenerated1_14-2"> best game of the decade.

Links

 * 1) "Half-Life 2 review". GameSpy.
 * 2) "Half-Life 2 Review". IGN.
 * 3) "Half-Life 2 Review for PC — Gaming Age". Gaming-age.com.
 * 4) "Half-Life 2". Metacritic.
 * 5) "Source Forts". Planet Half-Life. IGN.
 * 6) "Half-Life 2 (Xbox)". GameRankings.
 * 7) "Half-Life 2 PC Reviews". GameRankings.
 * 8) "Half-Life 2 PC Reviews". Metacritic.
 * 9) The Orange Box, Half-Life 2
 * 10) Valve Software, Half-Life 2