{{Platform|WOS|PS2|Mac OSX|Linux}}
{{Youmayd|the first game|the overall series|Half-Life universe}}
{{Game Infobox
November 19, 1998http//store.steampowered.com/app/70/ ''Half-Life'' on WikipediaSteam (software)|Steam
*'''PlayStation 2'''
November 14, 2001http//ps2.ign.com/objects/015/015631.html Half-Life (2001) on PlayStation 2. http//ign.com IGN.
|genre=WikipediaFirst-person shooter|First-person shooter
|mode=WikipediaSingle-player video game|Single-player, WikipediaMultiplayer video game|multiplayer
|platform=WikipediaMicrosoft Windows|Microsoft Windows, WikipediaPlayStation 2|PlayStation 2, WikipediaMac OS X|Mac OS X, WikipediaLinux|Linux,
Sega dreamcast (unrealesed) 
|rating=WikipediaEntertainment Software Rating Board|ESRB M (Mature)
|distribution=WikipediaSierra Entertainment|Sierra (previously), WikipediaElectronic Arts|Electronic Arts, WikipediaSteam (software)|Steam
|system=500 WikipediaHertz|MHz WikipediaCentral processing unit|processor, 96 WikipediaMegabyte|MB WikipediaRandom-access memory|RAM, and 16 MB WikipediaVideo card|video card
|input=*WikipediaKeyboard (computing)|Keyboard and WikipediaMouse (computing)|mouse (PC)
*WikipediaDualShock 2|DualShock 2 (PS2)
|series=''Half-Life universe|Half-Life''
|writer=Marc Laidlaw
|composer=*Kelly Bailey
*Ben Houge (PlayStation 2 main menu music)
|previous=''Half-Life Day One''
|next=''Half-Life Uplink''
{{Quote|Run. Think. Shoot. Live.|''Half-Life'' tagline|Half-Life}}

'''''Half-Life''''', stylized as '''''HλLF-LIFE''''', is a wikipediaScience fiction|science fiction first-person shooter developed and published by Valve. The player takes the perspective of scientist Gordon Freeman. Designed for Microsoft Windows, the game uses a heavily modified version of the wikipedia Quake engine|''Quake'' engine, called GoldSrc.http//store.steampowered.com/app/70/ ''Half-Life'' on WikipediaSteam (software)|Steam{{cite web | url=http//www.gamespot.com/features/halflife_final/index.html | title=The Final Hours of ''Half-Life'' Behind Closed Doors at Valve Software | publisher= GameSpot |accessdate=2006-09-03 }}

{{Main|Half-Life storyline}}

In ''Half-Life'', players assume the role of the protagonist, Gordon Freeman|Dr. Gordon Freeman, a recent WikipediaMassachusetts Institute of Technology|MIT graduate in theoretical physics, and also a recent employee at Black Mesa Research Facility|Black Mesa. After an experiment that goes horribly awry when an unexpected Resonance Cascade (an apparently completely fictitious occurrence) rips dimensional seams that devastate the facility, Gordon must fight to escape the now alien-infested facility as creatures from another world — known as Xen — subsequently enter in ever-increasing numbers through these dimensional seams.

The game is set during 200-|May 200- in a remote area of wikipediaNew Mexico|New Mexico, USA at the Black Mesa Research Facility; a fictional complex that bears many similarities to both the WikipediaLos Alamos National Laboratory|Los Alamos National Laboratory and WikipediaArea 51|Area 51.

As Freeman tries to make his way out of the ruined facility to find help for the injured, he soon discovers he is caught between two sides the hostile aliens, and the Hazardous Environment Combat Unit, a military force dispatched to cover up the incident — including eliminating Freeman & the rest of the Black Mesa Science Team. Throughout the game, a mysterious figure known as the G-Man regularly appears, apparently monitoring Freeman's progress. Ultimately, Gordon uses the cooperation of surviving scientists & security officers to work his way to the mysterious Sector F Lambda Complex|Lambda Complex, where a team of scientists teleport him to the alien world Xen, where he must destroy the Nihilanth, the creature keeping Xen's side of the dimensional rift open.

''Half-Life'''s plot was originally inspired by the computer games ''WikipediaDoom|Doom'' and ''WikipediaQuake|Quake'' (both produced by Wikipediaid Software|id Software), WikipediaStephen King|Stephen King's novella ''WikipediaThe Mist|The Mist'', and an episode of ''WikipediaThe Outer Limits (1963 TV series)|The Outer Limits'' called "WikipediaThe Borderland|The Borderland". Valve’s in-house writer and author, Marc Laidlaw, who wrote the books ''WikipediaDad's Nuke|Dad's Nuke'' and ''WikipediaThe 37th Mandala|The 37th Mandela'', later developed and expanded the plot. However, the most distinctive aspect of the game is not the plot itself, but rather the way it is presented to the player.

The game tells the story by flowing into scripted sequences that are integrated as part of the game rather than as cutscene intermissions. These sequences range from the introduction of major plot points such as the Resonance Cascade to bringing the player into a particularly difficult part of a level. Two of the intended results of this style of presentation were to increase immersion & to maintain a contiguous narrative that keeps the player's interest throughout. This differed from games at the time, making ''Half-Life'' distinct, as well as defining conventions that would last for years to come.

Valve implemented other factors to heighten the feeling of immersion, such as preventing the player from seeing or hearing their own character, who remains a silent protagonist throughout the game, and ensuring that the player rarely loses the ability to control Gordon Freeman|Gordon, even during monologues. This constant experience of the game allowed players to totally fulfill and customize, almost, the role of Gordon, whilst letting them know who they were playing as. The scripted sequences maintain flow by keeping the player immersed in the game, whereas cutscenes in other contemporary games had often been a diversion from previous segments of gameplay. The levels for ''Half-Life'' were also divided into small sections to minimize long interruptions from loading.

*Gordon Freeman
*The G-Man
*Eli Vance {{C|Retcons|Retcon}}
*Gina Cross {{C|As Holographic Assistant}}
*Barney Calhoun {{C|Cameo}} {{C|Retcons|Retcon}}
*Wallace Breen {{Mo}}
*Arne Magnusson {{C|Retcons|Retcon}}
*Black Mesa Science Team|Black Mesa Scientists
*Black Mesa Security Force|Black Mesa Security Guards

*'''CategoryXen creatures|Xen aliens'''
**Alien Controller
**Alien Grunt
**Vortigaunt|Alien Slave (Later known as Vortigaunt)
**Standard Headcrab|Headcrab
**Standard Zombie|Zombie
*'''Hazardous Environment Combat Unit'''
**Hazardous Environment Combat Unit|HECU soldiers
**CategoryHECU Vehicles|HECU vehicles
**HECU Sentry Gun|Sentry Guns
*'''Black Ops'''
**Female Black Ops
**Male Black Ops

There are fourteen weapons available to players in both single-player and multiplayer games. Many reviews of ''Half-Life'' mentioned the impressive functionality and "usefulness" of all the weapons designed. Each weapon's damage profile is distinct, none feeling superfluous or excessively powerful; each has a specific advantage in the appropriate situation. The weapons are

*'''Crowbar''' A simple melee weapon with many advantages, that has become an iconic symbol of Gordon Freeman and the ''Half-Life'' series has a whole. Useful for breaking objects and bludgeoning approaching enemies such as Headcrabs.

*'''Glock 17''' The most basic ranged weapon. Accurate and with average stopping power, this 9mm pistol is unique in that it can be fired underwater. Standard issue with all Black Mesa Security Guards, ammunition is always plentiful. '''(If the HD Pack is installed, this gun will look like a Beretta M9)'''

*'''Colt Python|.357 Magnum''' (Colt Python revolver) Powerful and accurate with a slow rate of fire. Ammunition is also somewhat scarce, however it will often kill any enemy up to a Bullsquid with one shot.

*'''MP5''' Fully automatic with poor stopping power and accuracy, but high magazine capacity and rate of fire. Equipped with a grenade launcher. Standard issue with all HECU troops. It shares ammunition with the Glock 17. If the HD Pack is installed, this gun will look like an M4.

*'''HECU SPAS-12|SPAS-12''' Powerful at close range, but has a slow rate of fire and long reload time. Also comes with the ability to fire two shells at once, thus killing enemies more quickly. Issued to certain HECU soldiers. If the HD Pack is installed, this gun has folding stocks which stay closed.

*'''Black Mesa Crossbow|Crossbow''' The only sniper weapon in ''Half-Life''. Its projectile is highly accurate but slow moving, making it difficult to use against distant or fast moving targets. Similar to the Glock 17, it can be fired underwater.

*'''Hivehand''' Also known as the "Hornet Gun". The same weapon used by the Alien Grunts, this gun is a living creature, which appears to be a larva of some sort (because it sports no legs). Firing hornets which target and track enemies, this gun has a short firing time, and is also less powerful. However, it has the advantage of infinitely recharging ammunition. Can also fire hornets directly (although with no homing ability, but a somewhat increased stopping power).

*'''HECU RPG|RPG''' Extremely powerful, but must be reloaded after each shot. Alternate fire activates/deactivates a laser sight; with the laser sight active, the rockets will track the laser to its target, making it useful for taking down helicopters and other flying vehicles or long-range enemies. Similar to the Glock 17 and Crossbow, it can be fired underwater but the rocket becomes much slower.

*'''Tau Cannon''' An experimental weapon that rapidly shoots beams of tau particles that reflect off surfaces if hit indirectly. Secondary fire charges the weapon up to fire a more powerful beam that can penetrate thin walls and pushes the user in the opposite direction. The recoil is deliberately exaggerated in multiplayer so the player can "Gauss jump" very high and reach hidden areas or escape opponents. This feature is a deliberate nod to "rocket jumping" in ''Quake'' (which is not possible in ''Half-Life''). If the gun is kept charged for too long (about 10 seconds), it overloads and discharges, damaging its wielder, as comically represented just before its discovery by Gordon.

*'''Gluon Gun''' This experimental weapon, named by its creator, fires out a beam of concentrated energy that disrupts its target's molecules. It looks and operates similarly to the proton pack used by the characters in the movie ''WikipediaGhostbusters|Ghostbusters''. Because of its internal weapon name, weapon_egon, it is also known as the Egon gun; this is probably a reference to the ''Ghostbusters'' character WikipediaEgon Spengler|Egon Spengler.

*'''Mk 2 Grenade''' A handheld thrown explosive, similar to most grenades. It explodes after 5 seconds and can be bounced off walls. Issued to HECU grunts, supplies are often found in supply depots.

*'''HECU Laser Tripmine|Laser Tripmine''' A high-explosive Claymore mine-like device that can be attached to walls. It is set off either by damaging the mine or by crossing through the laser "tripwire" emitted from it. In multiplayer, it can be used to form steps by attaching them to the wall in a stair-like fashion, forming a route to jump up.

*'''Satchel Charge''' A potent explosive that can be thrown a short distance and detonated remotely. They are often scarce and hard to find.

*'''Snarks''' Aggressive and small alien creatures that quickly pursue their target, pestering and biting, until finally exploding after several seconds (or if shot). If they cannot locate a hostile target, they will turn on the player that set them loose, making them, at times, enemies.

FileBaby ad2.jpg|left|200px|Early promotional poster, with a Lambda logo in a baby's eye.|thumb

''Half-Life'' was the first product for Kirkland, Washington-based developer Valve Software, which was founded in 1996 by former Microsoft employees Mike Harrington and Gabe Newell. They settled on a concept for a horror-themed 3D action game, and licensed the ''WikipediaQuake (video game)|Quake'' engine from id Software. Valve eventually modified the engine a great deal, notably adding skeletal animation and WikipediaMicrosoft Direct3D|Direct3D support; a developer later stated that seventy percent of the engine code was rewritten.PC Accelerator magazine At first Valve had difficulties finding a publisher, many believing their project "too ambitious" for a studio headed by newcomers to the video game industry. However, Sierra On-Line had been very interested in making a 3D action game, especially one based on the ''Quake'' engine, and so signed them for a one-game deal.

The original code name for ''Half-Life'' was ''Quiver'', after the Arrowhead military base from Stephen King's novella ''The Mist'', which served as early inspiration for the game. Gabe Newell explained in an interview that the name ''Half-Life'' was chosen because it was evocative of the theme, not clichéd, and had a corresponding visual symbol the Greek letter Lambda logo|lambda, which represents the WikipediaExponential decay|decay constant in the WikipediaHalf-life|half-life equation.

The first public appearances of ''Half-Life'' came in early 1997; it was a hit at the WikipediaElectronic Entertainment Expo|Electronic Entertainment Expo that year, where they primarily demonstrated the animation system and artificial intelligence. Valve Software hired science fiction author Marc Laidlaw in August 1997 to work on the game's characters, story, and level design. ''Half-Life'' was originally planned to be shipped in late 1997, to compete with ''WikipediaQuake II|Quake II'', but was postponed when Valve decided the game needed significant revision.

In a 2003 "Making of..." feature in ''WikipediaEdge (magazine)|Edge'', Newell discussed the team's early difficulties with level design. In desperation, a single level was assembled including every weapon, enemy, scripted event and level design quirk that the designers had come up with so far. This single level inspired the studio to press on with the game. As a result, the studio completely reworked the game's artificial intelligence and levels in the year leading up to its release. At E3 1998 it was given Game Critics Awards for "Best PC Game" and "Best Action Game" at the expo. The release date was delayed several times in 1998 before the game was finally released in November of that year.

FileHL PS2 cover.jpg|right|200px|PlayStation 2 cover.|thumb

The game had its first major public appearance at the 1997 Electronic Entertainment Expo, where it was widely acclaimed.

On its release, critics hailed its overall presentation and numerous scripted sequences, and it won over 50 PC Game of the Year awards.{{cite web |url=http//www.valvesoftware.com/about.html |title=About Valve |accessdate=2008-02-28  |publisher=Valve Corporation}}{{cite web|url=http//www.valvesoftware.com/awards.html|title=Awards and Honors|publisher=Valve Corporation|accessdate=2005-11-14}} Its gameplay influenced first-person shooters for years to come, and it has since been regarded as one of the greatest games of all time.{{cite web | url=http//www.gamasutra.com/features/20060901/quantum_01.shtml | title= The Gamasutra Quantum Leap Awards First-Person Shooters | accessdate=2006-09-03|publisher=Gamasutra }} As of November 2008, ''Half-Life'' has sold 9.3 million copies.{{cite web |url=http//www.washingtonpost.com/wp-dyn/articles/A52849-2004Nov15.html?nav=rss_technology |title=Half-Life 2's Real Battle |author=Mike Musgrove |publisher=Washington Post |date=2004-11-16 |accessdate=2008-02-28}} As of July 14, 2006, the ''Half-Life'' franchise has sold over 20 million units.{{cite press release |title=Half-Life is 10 Today |publisher=Valve Corporation|Valve |accessdate=2008-02-28 |date=2006-07-14 |url=http//store.steampowered.com/news/2039/}} According to GameSpy, ''Half-Life'' is the most played online PC game (excluding MMORPGs), ahead of ''Half-Life 2''.{{cite web |accessdate=2008-09-26 |url=http//archive.gamespy.com/stats/ |title=Top Game Servers By Players |publisher=GameSpy}} In celebration of the game's 10th anniversary, Valve lowered the price of ''Half-Life'' from $9.99 USD to $0.98 on November 19, 2008 for three days.http//www.gamespot.com/news/6201390.html Half-Life decays to $1 on GameSpot

''Half-Life'' was ported to the PlayStation 2 by Gearbox Software and released in 2001. This version of the game had a significant overhaul in terms of both character models, weapons, and more advanced and extended levels and general map geometry. Also added in was a head-to-head play and a co-op expansion called ''Half-Life Decay'' that allowed players to play as the two female scientists Gina Cross and Colette Green at Black Mesa.

Versions for the Sega Dreamcast and Apple Macintosh were essentially completed, but never commercially released.

===Dreamcast version===
Gearbox Software was slated to release a port to the Sega Dreamcast under contract by Valve and their then publisher Sierra On-Line near the end of 2000. At the WikipediaEuropean Computer Trade Show|ECTS 2000, a build of the game was playable on the publisher's stand, and developers Randy Pitchford and Brian Martel attended to show it off and give interviews to the press. However, despite only being weeks from going gold, it was never commercially released; Sierra announced that ''Half-Life'' on Dreamcast was canceled "due to changing market conditions" (presumably the first-party abandonment of the failing Dreamcast). The following year Sierra On-Line showed a PlayStation 2 port at E3 2001. This version was released in North America in late October of the same year, followed by a European release just a month later. Around the same time, ''Half-Life Blue Shift'', which was intended to be a Dreamcast exclusive midquel, was released on PC as the second ''Half-Life'' expansion.

Although it has never officially been released, the Dreamcast version was leaked onto the Internet, and was proven fully playable. The leak contains the full versions of ''Half-Life'' and ''Blue Shift'', both with an early version of the ''High Definition Pack'' (it was from this port that the pack was spawned). Although, the leak has a somewhat inconsistent frame rate (though never to the point of unplayability) and lengthier load times when the player moves from area to area (around ten seconds, while today's average PC can load an area in around one and a half). In addition, there are some saving problems; the number of blocks required to save on a WikipediaVMU|VMU increases rapidly as the player reaches the end of a level, then drops at the start of the next. While the game allows the player to remove files to increase space, sometimes it still isn't enough.

The console's mouse and keyboard peripherals are supported, if preferred to the standard controller. If the controller is used, the game adds an auto-aim feature, so that when an enemy nears the center of the player's vision, the aiming crosshair will shift over toward the enemy to make shooting them easier. The game's controls are customizable. The game has no multiplayer mode, and lacks the parental feature of the PC version (players cannot turn the WikipediaGibs|gibs off). It does have an interesting password feature, however; with three dials, the user makes various phrases, such as "Otis Loves Dreamcast" (god mode), "Fear and Gravity" (jump to Xen, in ''Half-Life''), or "Barney Goes To Work" (skip the intro in ''Blue Shift'' and jump right into the main game, pre-resonance cascade).

===Macintosh and Linux version===
Though more or less complete and ready for mass production, the Macintosh port of ''Half-Life'' was scrapped because of incompatibility with the PC version's multiplayer mode. Additionally, concerns over the task load associated with providing technical support on more than one platform at once may have contributed to its initial demise.

In early 2013, Valve released a beta version Half-Life for Mac OS X and Linux in secret. While STEAM still listed the game as windows only, it could be downloaded and played on Mac OS X and Linux Computers. It was initially listed as "Half Life (beta)" when played on Mac and Linux, even if it was listed as "beta" it still featured the complete fully-playable game. The game could be purchased directly from the Mac OS X and Linux Clients as well.  Later in 2013 the stable release of the game was officially released for Linux and Mac, listing it as officially available for these platforms on Steam.

To experience first-hand the processes mod-makers would have to go through with the new engine, Valve ported ''Half-Life'' (dubbed ''Half-Life Source'') and ''http//counterstrike.wikia.com/wiki/Counter-Strike  Counter-Strike'' to their new Source engine. ''Half-Life Source'' is a straight port, lacking new content or the ''Blue Shift'' Half-Life High Definition Pack|High Definition Pack. However, it does take advantage of vertex and pixel shaders for more realistic water effects, as well as ''Half-Life 2''’s realistic physics engine. They also added several other features from ''Half-Life 2'', including an improved dynamic lightmap, vertex map, and shadowmap system with cleaner, higher resolution and specular texture and normal maps. They also utilized the use of the render-to-texture soft shadows found in ''Half-Life 2''’s Source engine, along with polygonal 3D skybox replacements in place of the old 16-bit color prerendered bitmap skies. Also redesigned was the Black Mesa Crossbow|Crossbow that will pin its targets to a nearby wall (if they're close enough), and the Colt Python, which will zoom in as if it were multiplayer. The Source engine itself, however, is not perfect. Certain control issues are generally regarded as being a problem, such as ladder bounce (where disconnecting from a ladder gives a sideways vector boost, which can be highly undesirable when trying to move near a ladder on a platform over a fall), fall push (where moving off a platform into a fall gives a sideways vector boost), and jumping from platforms (where the graphics engine tends to lead the player to think a jump can be made later than it actually can). Naturally, the ''Half-Life'' port possesses the Source engine's control weaknesses as well as its graphical strengths. ''Half-Life Source'' is available with special editions of ''Half-Life 2'' and on WikipediaSteam (software)|Steam. This port has been criticized, however, for not utilizing many of the features of the Source engine found in ''Half-Life 2'', as it still used textures and models from the original game. Due to this, a third-party remake called ''Black Mesa (mod)|Black Mesa'' is under development. On September 26, 2005, a port of ''Day of Defeat'' to Source (dubbed ''wcdayofdefeatDay of Defeat Source|Day of Defeat Source'') was released.

On June 10, 2005, Valve announced through their WikipediaSteam (software)|Steam update news service an upcoming port of ''Half-Life Deathmatch Source'', the multiplayer portion of the original game, much in the same fashion as the earlier released ''Half-Life Source''. No exact release date was given, simply the words "In the coming weeks..." On May 1, 2006, ''Half-Life Deathmatch Source'' was released.http//store.steampowered.com/app/360/ ''Half-Life Deathmatch Source'' on Steam

Two expansion packs made by the developer Gearbox Software have been released for the PC version ''Half-Life Opposing Force'' (1999) and ''Half-Life Blue Shift'' (2001). ''Opposing Force'' returns the player to Black Mesa during the events of ''Half-Life''’s storyline, but this time from the perspective of the U.S. Marines sent to cover up the incident. It introduced several new weapons (most notably the M249 Squad Automatic Weapon|M249 SAW LMG and a Barnacle grappling gun), new non-player characters, both friendly and hostile (Otis Laurey the security guard and the Race X aliens, respectively) and new, previously unseen areas of the facility. The expansion is much shorter than ''Half-Life'', having Twelve chapters to the original's nineteen.

''Blue Shift'' returns the player to ''Half-Life'''s storyline once more, this time as one of the facility's security guards. Originally developed as a bonus mission for the canceled Dreamcast version, ''Blue Shift'' came with an optional ''High Definition Pack'' that could update the look of ''Half-Life'', ''Opposing Force'', and the new ''Blue Shift'' content. In particular, the models' polygon count and texture resolutions were increased, and some changes were made to the in-game sounds, most notably the HECU SPAS-12|Shotgun. ''Blue Shift'' had relatively little new content compared to ''Opposing Force'' aside from a few models (jacket-less scientists and security guards, Otis, and Rosenberg|Dr. Rosenberg), all content was already present in the original ''Half-Life''.

''Half-Life Decay|Decay'' was another expansion by Gearbox, released only as an extra with the PlayStation 2 version of ''Half-Life''. The add-on featured co-operative gameplay in which two players could solve puzzles and fight alongside against the many foes in Black Mesa. An Unofficial PC ported of this expansion released in September 22, 2008 by Ukrainian Developer as a Modification. 

In 2000, a pack titled the ''Half-Life Platinum Collection'' was released, with these games included
*''WikipediaTeam Fortress Classic|Team Fortress Classic''
*''Half-Life Opposing Force''

In 2002, the pack was re-released with ''Half-Life Blue Shift'' included.

Today it is known on Steam as the ''http//store.steampowered.com/sub/40/ Half-Life 1 Anthology'' without ''Counter-Strike''.

The Game of the Year edition of ''Half-Life'' came packaged with ''Team Fortress Classic''.

After its release in 1998, ''Half-Life'' saw fervent support from independent game developers, due in no small part to support and encouragement from Valve Software. Valve Hammer Editor|Worldcraft, the level-design tool used during the game's development, was included with the game software. Printed materials accompanying the game indicated Worldcraft's eventual release as a retail product, but these plans never materialized. Valve also released a software development kit, enabling developers to modify the game and create mods. Both tools were significantly updated with the release of the version patch. Many supporting tools (including texture editors, model editors, and rival level editors like the multiple engine editor WikipediaQuake Army Knife|QuArK) were either created or updated to work with ''Half-Life''.

''Half-Life'''s code has been released and is being used as a base for many multiplayer mods such as the immensely popular ''WikipediaCounter-Strike|Counter-Strike''. Other popular multiplayer mods include ''WikipediaTeam Fortress Classic|Team Fortress Classic'', ''wcdayofdefeatDay of Defeat|Day of Defeat'', ''Deathmatch Classic'', ''Action Half-Life'', ''http//www.moddb.com/mods/firearms Firearms'', and ''http//www.unknownworlds.com/ns/ Natural Selection''. ''Team Fortress Classic'' and ''Deathmatch Classic'' were both developed in-house at Valve Software. Some mods, such as ''Counter-Strike'' and ''Day of Defeat'', that began life as the work of independent developers (self-termed "modders"), later on received aid from Valve. There was even a free team-based multiplayer mod called ''Underworld Bloodline'' created to promote the Sony Pictures film ''WikipediaUnderworld (2003 film)|Underworld''.

Numerous single-player mods have also been created, such as ''USS Darkstar'' (1999, a futuristic action-adventure on board a zoological research spaceship), ''http//www.moddb.com/mods/xeno-project-i-ii The Xeno Project 1'' and ''2'' (1999–2005, a two-part mod starting in Xen and again including spaceships), ''http//www.planetphillip.com/posts/edge-of-darkness-half-life/ Edge of Darkness'' (2000, which features some unused ''Half-Life'' models), ''http//www.moddb.com/mods/absolute-redemption Half-Life Absolute Redemption'' (2000, which brings back Gordon Freeman for four additional episodes and another encounter with the G-Man), ''They Hunger'' (2000–2001, a survival horror total conversion trilogy involving zombies), ''http//www.poke646.com/ Poke 646'' (2002, a follow-up to the original ''Half-Life'' story with improved graphics), and ''http//www.moddb.com/mods/xen-warrior Xen-Warrior'' (2002–2004, based on ''Half-Life Chronicles'', the player controls an Alien Grunt, similar to ''http//www.moddb.com/mods/point-of-view Point of View'' in which players take on the role of a Vortigaunt and ''http//www.moddb.com/mods/half-life-zombie-edition Half Life Zombie Edition'', where the player plays as a Headcrab).

Some ''Half-Life'' modifications eventually landed on retail shelves. ''Counter-Strike'' was the most successful, unexpectedly becoming the biggest selling online game to date and having been released in five different editions as a standalone product (2000), as part of the ''Platinum Collection'' (2000), ''wccounterstrikeCounter-Strike Condition Zero|Counter-Strike Condition Zero'' (2004), and the newest addition, ''wcCounter-Strike Source|Counter-Strike Source'', which runs on ''Half-Life 2'''s Source engine. ''Team Fortress Classic'' has had a visual upgrade to the Source engine, becoming the stylized ''wcteamfortress2Team Fortress 2|Team Fortress 2''. ''Day of Defeat'' also received the Source treatment becoming ''wcdayofdefeatDay of Defeat Source|Day of Defeat Source''. ''WikipediaGunman Chronicles|Gunman Chronicles'' (2000), a futuristic Western movie-style total conversion with emphasis on its single-player mode) was also released as a stand-alone product.

The sequel ''Half-Life 2'' was merely a rumor until it was finally revealed at E3 in May 2003, which ignited a firestorm of hype surrounding the game. The player again takes the role of Gordon Freeman, this time several years after the Black Mesa incident in the dystopian City 17, where he must fight as part of a rebellion against an oppressive alien regime. After a series of controversies and delays, ''Half-Life 2'' was released on November 16, 2004.

''Half-Life 2 Episode One'' continues the story plot, along with ''Half-Life 2 Episode Two'' which was released in October 2007. No date has been set for the release of the final episode, which will end the ''Half-Life 2'' story arc.

{{Main|Half-Life soundtrack}}

''Half-Life's'' soundtrack consists of specially composed tracks by Kelly Bailey, who also composed much of the music for the rest of the series. He was also responsible for the game's in-game sounds.

*Director Quentin Tarantino (who is said to be a ''Half-Life'' fan) has reportedly considered the possibility of directing a movie adaptation. Valve has stated however that they have had no contact with Quentin Tarantino or any of "his people". Valve went on to comment that, "We've had many conversations with folks in Hollywood, but have no commitments for a HL movie at this time." Also, many Hollywood scripts for a ''Half-Life'' movie have been sent to Valve, but turned away, as Valve said they all "sucked".{{cite web |url=http//www.eurogamer.net/articles/i_valve_060606?page=2 |title=Opening the Valve Interview |author=Tom Bramwell |publisher=Eurogamer |date=2006-06-06}}

*The ''Half-Life'' series draws some inspiration from various adaptations of H. G. Wells's ''WikipediaThe War of the Worlds|The War of the Worlds''; the Vortigaunts who appear throughout the series are almost identical to the Mor-Tax aliens from the ''WikipediaWar of the Worlds (TV series)|War of the Worlds'' TV series.

*''Half-Life'', as well as its three expansions, are named after scientific terms. "Half-life" refers to WikipediaRadioactive decay|radioactive decay.

*When Gordon puts on his hazard suit in the first level, there are two empty hazard suit slots. According to ''Decay'' developer Gearbox Software|Gearbox's CEO Randy Pitchford these belonged to (or were used by) ''Decay'' protagonists Gina Cross and Colette Green.

*''Half-Life'' holds the record for the "Best-Selling First-Person Shooter of All Time (PC)" in the ''WikipediaGuinness World Records Gamer's Edition|Guinness World Records Gamer's Edition 2008''.

*Due to censorship, in the German version of ''Half-Life'', the HECU grunts have been replaced with Robot Grunts, the Robot Grunt blood is now changed to oil, and there are machine part gibs for the Grunts. In addition, blood and other violent parts have been removed, and Scientists and Security Guards now sit down and shake their heads, rather than dying.{{YouTube|alIBAUO_CUM|Video ''Half-Life'' German Version}}

*Although enemies and allies that are alive are solid; players cannot walk through them without the noclip cheat. But when they are killed, they remain solid for a while, then turns non-solid; players can walk through them like they were nothing.

*Surprisingly though, bugs and glitches that are triggered throughout the game can bug enemies that are killed. For instance, a zombie making a scripted sequence while killed will play it's death animation and being rendered non-solid, then redo it's scripted animation, albeit being dead. 

*Due to many request from fans, many modders have been trying to port Half-life to the wikipediaPlayStation Portable|PlayStation Portable.

*If Gordon kills any important NPC (i.e. the scientist opening the portal) a black screen comes up, implying that the G-Man is intentionally evaluating Gordon's actions throughout the entire game.


FileHL Old Jewel Case front.jpg|Old Jewel Case front.
FileHL Old Jewel Case back.jpg|Old Jewel Case back.
FileHL ad page 1.jpg|First page print ad for ''Half-Life'', slated to appear in the April CGW and PC Gamer.
FileHL ad page 2 and 3.jpg|When you open the first page reveal this two-page fold out.
FileHL adturnrunpage1.jpg|Another ad of ''Half-Life'' turn, run.
FileHL adturnrunpage2.jpg|Ditto.
FileCascade4.jpg|Destruction reigns, moments after the catastrophic resonance cascade.
FileIonization Chambers Unforeseen Consequences.jpg|Unforeseen consequences aliens start entering the facility.
FileEli help.jpg|The scientists are still in shock after the explosion.
FileSector_b_lower_canal.jpg|More aliens get in, forcing Gordon to take to the maintenance areas.
FileSmithers_found.jpg|Scared scientists try and keep hidden.
FileTentacle_pit.jpg|The aliens just keep getting bigger.
FileApprehension_vort_attack.jpg|Vortigaunts start attacking.
FileHL BMRF ResidueProcessing.jpg|Glowing vats of radioactive waste.
FileLand_mine_explode.jpg|Security measures start trying to kill the wrong people.
FileBlack Mesa valley goldsrc.jpg|Precarious leaps and narrow ledges are all that's between Gordon and death.
FileHounds_resting.jpg|What have those scientists been doing in secret?
FileSterilizer_1_powerup.jpg|More secrets.
FileC3a2e0000.jpg|A descent into new, mysterious territory.
FileLambdaTeleportationSystem.jpg|The hidden Lambda Complex, where Gordon finally enters Xen.
FileC4a20004.jpg|Strange alien worlds that float by some unknown means.

{{Imagecat|Half-Life images}}

==External links==
*The original http//web.archive.org/web/20040327035902/http//www.half-life.com/ ''Half-Life'' official website
*{{YouTube|s1JupoC4-EI|Early ''Half-Life'' teaser released in 1997}}
*{{YouTube|PU5mSUN8HF4|Early ''Half-Life'' trailer}}
====E3 1998====