The series' logo, an orange lambda, is a prominent symbol throughout the series
November 19, 1998
|Latest release||Half-Life: Alyx|
March 23, 2020
The original Half-Life, Valve's first product, was released in 1998 to critical and commercial success. Players control Gordon Freeman, a scientist who must survive an alien invasion. The innovative scripted sequences were influential on the FPS genre, and the game inspired numerous community-developed mods, including the multiplayer games Counter-Strike and Day of Defeat. Half-Life was followed by the expansions Opposing Force (1999) and Blue Shift (2001), developed by Gearbox Software.
In 2004, Valve released Half-Life 2 to further success, with a new setting and characters and physics-based gameplay. The series continued with the episodic games Half-Life 2: Lost Coast (2005), Half-Life 2: Episode One (2006) and Half-Life 2: Episode Two (2007). A planned third episode, and games developed by Junction Point Studios and Arkane Studios, were canceled. The first game in the Portal series, set in the same universe as Half-Life, was released in 2007.
Valve experimented with further Half-Life projects for over a decade. After years of speculation, Valve released its flagship virtual reality game, Half-Life: Alyx, in 2020. Set before Half-Life 2, players control Freeman's ally Alyx Vance in her quest to defeat the alien Combine.
|1999||Half-Life: Opposing Force|
|2001||Half-Life: Blue Shift|
|Half-Life 2: Deathmatch|
|2005||Half-Life 2: Lost Coast|
|2006||Half-Life Deathmatch: Source|
|Half-Life 2: Episode One|
|2007||Half-Life 2: Episode Two|
Half-Life was Valve's first product, released on November 19, 1998. Players control Gordon Freeman, a theoretical physicist, after the Black Mesa Research Facility accidentally causes a dimensional rift which triggers an alien invasion. The game was published by Sierra Studios and released for Windows, and was ported by Gearbox Software to PlayStation 2 in 2001. Valve later converted the game to use their Source engine. Half-Life received critical acclaim, critics hailing its overall presentation and numerous scripted sequences. The game won over 50 Game of the Year awards and its gameplay has influenced first-person shooters for years to come. Half-Life has since been regarded as one of the greatest games of all time.
Half-Life was followed by an expansion pack, Opposing Force, on November 1, 1999. Unlike Half-Life, Opposing Force was developed by Gearbox Software, although it was still published by Sierra Studios. Opposing Force was first announced as a mission pack for Half-Life in April 1999, and was released for the Windows version of the game. The player no longer assumes the role of Gordon Freeman, but rather sees the later events of the first game from the perspective of a US Marine corporal, Adrian Shephard. Shephard is initially assigned to cover up the events at Black Mesa, but is soon left isolated and has to fight to survive against a new group of alien invaders and black operations units.
Opposing Force was received favorably by critics, many citing the game as being as influential on setting expansion pack standards as the original game had been in influencing the overall genre. The game won the Computer Game of the Year Interactive Achievement Award of 2000 from the Academy of Interactive Arts & Sciences.
Gearbox went on to develop Blue Shift, Half-Life's second expansion pack. Like Opposing Force, Blue Shift was published by Sierra Entertainment. Announced in 2000, the game was initially developed as a bonus campaign for the Dreamcast port of Half-Life; however, the port was cancelled and Blue Shift was instead released for Windows on June 12, 2001.
Blue Shift puts the player in the position of Barney Calhoun, a security guard working at Black Mesa. The game takes place within the early parts of Half-Life, with Calhoun attempting to escape the facility with a small group of scientists. Blue Shift also includes a High Definition pack, which upgrades the quality of the models and textures in both Blue Shift and the preceding games in the series. Critics praised the atmosphere and new graphics, but criticized the lack of new content and short length.
The third expansion for Half-Life was Decay. The game was again developed by Gearbox and published by Sierra. However, unlike previous games, Decay is only available with the PlayStation 2 version of Half-Life. Decay is unique within the Half-Life series as the only cooperative game—two players must work together to progress through the game. Decay focuses on two of Freeman's colleagues, Gina Cross and Colette Green, as the two work with other scientists to counter the effects of the dimensional rift and ultimately attempt to close it.
Released on November 14, 2001, Decay received a weak but overall positive reception from critics, many reviewers stating that it was fun to play through with a friend, but that the game's more puzzle-oriented gameplay detracted from the overall experience. An unofficial Windows port was released in September 2008.
On November 16, 2004, Valve released Half-Life 2. The game had a six-year development cycle, which saw several delays and the leak of the game's source code. Half-Life 2 returns the player to the role of Gordon Freeman. Set twenty years after the original game, Earth has been occupied by the Combine, a transdimensional race that exploited the events of the first game to invade. The G-Man inserts Freeman into City 17 in Eastern Europe to combat the Combine occupation. Half-Life 2 garnered near-unanimous positive reviews and received critical acclaim much like its predecessor, winning over 35 Game of the Year awards for 2004. Considered one of the greatest video games of all time, the game has been critically praised for its advances in computer animation, sound, narration, computer graphics, artificial intelligence, and physics. Half-Life 2 was the first game to use Valve's Steam content delivery system, a system that eventually led to Valve falling out with publisher Sierra Entertainment.
On October 27, 2005, Valve released Lost Coast, a short, playable tech demo demonstrating high dynamic range rendering. Consisting of a single map, Lost Coast was based on a cut segment of Half-Life 2. The player, as Freeman, climbs a cliff to destroy a Combine artillery launcher in a monastery.
In May 2006, Valve announced a trilogy of episodic games that would continue the Half-Life 2 story, with the final episode planned for release by Christmas 2007. Newell said that the approach would allow Valve to release products more quickly after the six-year Half-Life 2 development, and that he considered the trilogy the equivalent of Half-Life 3. According to Newell, where Half-Life saw the G-Man transform Freeman into his tool, and Half-Life 2 saw Freeman being used by G-Man, the episodes would see G-Man lose control.
Episode One was released on June 1, 2006. The player controls Freeman as he and Alyx escape City 17 before a dark energy reactor core destroys it. It introduced several graphical effects, including new lighting features and more advanced facial animation. The story focuses on Alyx. Episode One received a generally positive critical reaction, although the short length was a common point of criticism.
Episode Two was released for Windows, Xbox 360, and PlayStation 3 on October 10, 2007 as part of the compilation The Orange Box. It was distributed digitally on Steam and at retail by Electronic Arts. Episode Two focuses on expansive environments, travel, and less linear play. As Freeman, the player travels with Alyx into the surrounding countryside, pursued by Combine forces. Episode Two's new technologies and gameplay features were praised by reviewers; however, though it was significantly longer than Episode 1, the length was again a point of criticism.
Valve released Half-Life: Alyx, a virtual reality (VR) game, on March 23, 2020, for Windows. A prequel to Half-Life 2, players control Alyx as she and her father Eli establish the resistance against the Combine in City 17. Described by Valve as its "flagship" VR game, it was developed using the Source 2 engine and supports all PC-compatible VR headsets. Players use VR to interact with the environment and fight enemies, using gravity gloves to manipulate objects, similarly to the gravity gun from Half-Life 2. Alyx was released to acclaim. Reviewers at publications such as VG247, Tom's Hardware, and Video Games Chronicle have said that the game is VR's "killer app".
Episode Three was announced in 2006, with a release date of Christmas 2007. Concept art surfaced in 2008. Valve worked with sign language and was working on a deaf character. Valve released little information about Episode Three in the following years; though Valve still discussed Half-Life, there was no clarity on whether Episode Three was coming, whether Valve was instead planning Half-Life 3, or if Valve had forgone the property to better support the popular Counter-Strike: Global Offensive. In March 2010, Newell spoke of "broadening the emotional palette" of the series, and how the next Half-Life game may return to "genuinely scaring the player". In 2011, he said: "We went through the episodes phase, and now we’re going towards shorter and even shorter cycles ... For me, 'entertainment as a service' is a clear distillation of the episodic content model." That year, Wired described Episode Three as vaporware.
After Episode Two, Valve abandoned episodic development, as they wanted to create more ambitious installments. According to level designer Dario Casali, with Episode Two, "We found ourselves creeping ever forward towards, ‘Well, let's just keeping putting more and more, and more, and more stuff in this game because we want to make it as good as we can,' and then we realized these episodes are turning more into sequels." Additionally, Valve had started development of Source 2 at the time of Episode 2's release; as developing Half-Life 2 and the original Source engine simultaneously had created problems, Valve delayed development of a new Half-Life until the engine was completed, by which time they were experimenting with virtual reality.
In 2016, Half-Life writer Marc Laidlaw left Valve. Laidlaw said he had intended Episode Three to end the Half-Life 2 plot arc, at which point he would "step away from it and leave it to the next generation". He planned an ending similar to previous games, with Freeman left "in an indeterminate space, on hold ... So one cliffhanger after another ... I expected every installment would end without resolution, forever and ever."
In 2017, Laidlaw posted a short story, "Epistle 3", on his website. Laidlaw described the story as a "snapshot of a dream I had many years ago". Journalists interpreted it as a summary of what could have been the plot for Episode Three. The story features characters with names similar to Half-Life characters, such as "Gertie Fremont" for Gordon Freeman. Substituting the characters with their Half-Life counterparts, the story sees Freeman and his allies travel to the Arctic to board the Borealis, a ship that travels erratically through time and space, where they "confront myriad versions" of themselves. They rig the ship to travel to the heart of the Combine empire and self-destruct, but the explosion is not sufficient to destroy the Combine's Dyson Sphere. Alyx is taken by the G-Man and Gordon is rescued by the Vortigaunts, with most of the Resistance dead and the success of their uprising uncertain.
After Laidlaw published the story, some players left negative reviews for Dota 2 on Steam, believing that Valve had forgone the Half-Life series. The story led to a number of fan efforts to create Episode Three. In 2020, designer Robin Walker denied that the "Epistle 3" story had been Valve's plan for Episode Three, and said that it was likely just one of many ideas by Laidlaw.
Junction Point Studios episodeEdit
Another episode was under development by Junction Point Studios, led by Warren Spector. According to Spector, the episode showed how Ravenholm became the town seen in Half-Life 2, infested with headcrabs and zombies, and saw the return of the character of Father Grigori. The game included a "magnet gun", which fired projectiles that magnetized metal surfaces and attracted objects and enemies, and would have been used for combat and puzzles. Junction Point worked on the game for a year, producing enough content to demonstrate one section of the game, and a vertical slice that demonstrated the magnet gun. Valve became uninterested in the project and Spector dropped it in favor of Disney's Epic Mickey. Images of the game appeared in early 2017.
In 2007 or 2008, Valve gave the Junction Point project to Arkane Studios in Lyon, France. They developed it into a standalone game with the working title Ravenholm. Players controlled Adrian Shepard from Opposing Force, working alongside Father Grigori, who had taken refuge in a psychiatric hospital. Grigori was experimenting with the effects of headcrab venom on himself, and would mutate through the story. The player would use the magnet gun and traps created by Grigori against enemies. Arkane also implemented a nailgun that could create paths to conduct electricity and set traps.
Valve gave Arkane freedom to develop Ravenholm, as they had with Gearbox and Opposing Force. Arkane sent their work to Valve for feedback and technical support. With approximately one year left of development, Valve canceled the project; Arkane founder Raphaël Colantonio believed that Valve decided it would be too expensive, and Laidlaw said that Valve felt the premise was creatively constrained. Ravenholm was first shown to the public in a 2020 Noclip documentary.
The Portal series, which takes place in the same universe as the Half-Life games, is a series of puzzle games developed by Valve. The first game in the series, Portal, was initially released alongside Episode Two in The Orange Box on October 10, 2007. The player controls a test subject named Chell as she moves through the laboratories of Black Mesa's primary rival, Aperture Science, completing various tests with a device that allows her to create linked portals in physical space. In the later stages of the game, the player battles GLaDOS, a corrupt artificial intelligence computer that monitors her every move. The game is the spiritual successor to Narbacular Drop, with many of the same team members working on the game. Portal has been acclaimed as one of the most original games in 2007, receiving praise for its unique gameplay and darkly humorous story. An Xbox Live Arcade expansion was released on October 22, 2008, and its sequel, Portal 2, was released on April 19, 2011.
In April 2000, Valve acquired the rights to the fan-made modification Counter-Strike. After some cooperation between the original team and Valve's developers, Valve sold the game in retail, retitled Half-Life: Counter-Strike. Set in various locations around the world with little connection to the events of the main Half-Life story, the game is a multiplayer shooter in which players assume the roles of members of combating teams of the governmental counter-terrorist forces and various terrorist militants opposing them. Due to originally being a mod of Half-Life, the game shared several assets with the 1998 game, including Black Mesa containers, vehicles, and scientists, with the Black Mesa logos visible in several maps in the retail version implicitly setting them in the same universe. It was bundled with Half-Life in many subsequent packages, including Half-Life: Platinum Pack and Half-Life: Platinum.
When Half-Life: Counter-Strike was remade as Counter-Strike: Source, it was bundled in all retail versions of Half-Life 2, as well as all of the initial digital versions. Some game journalists referred to it as "Half-Life 2's multiplayer version." Both the standard retail edition and the Bronze digital edition of Half-Life 2 came with Counter-Strike: Source, while the retail Collector's Edition and the digital Gold edition also included Day of Defeat: Source and Half-Life: Source. Half-Life: Counter-Strike spawned its own series which gradually became separate from the main Half-Life games, bar occasional references (such as an Easter egg referencing Portal present in Counter-Strike: Global Offensive).
The success of the Half-Life series has spurred the creation of several spin-off games for Half-Life 2. Codename Gordon is a two-dimensional Flash sidescroller shooter developed by NuclearVision, and was released over Valve's Steam online delivery system on May 18, 2004, as a promotional game for the then-upcoming Half-Life 2. The developer has since gone bankrupt, but the game itself can still be installed via a direct link to Steam, despite not being listed in the store. Codename: Gordon was well received by reviewers and the public, and attracted over 600,000 players in the first three weeks after its release. Reviewers praised the game for its gameplay and unique dialog style, but also criticized it for its improper optimization, and lack of opponent variety.
Characters from Half-Life have appeared in other games. Peggle Extreme, a special edition of Peggle bundled with the PC version of The Orange Box features levels based on Half-Life 2, Team Fortress 2 and Portal. The headcrab is also an unlockable character in Super Meat Boy when bought on Steam. The Headcrab also appeared in an April Fools event in the MMO Vindictus as an event item along with the Crowbar, possibly due to the game being created on the Source Engine as well. In the game Magicka there is a playable character (after the addition of a DLC), which closely resembles the original zombie from the Half-Life universe, equipped with a crowbar. Gordon also appears in Renegade Ops and the headcrab is available as a pet in Torchlight 2.
Half-Life has also inspired a number of fan-made mods, some which have gained recognition on their own. Black Mesa is a fan remake of the original Half-Life using the Source engine, which has been approved by Valve. Garry's Mod started as a sandbox mode using Half-Life 2 assets but since has become a commercial product and given users the ability to incorporate other assets. Among notable fan-made campaigns is Minerva, which was designed to extend the story from Half-Life 2.
The video game development company behind the Half-Life series, Valve, was founded in 1996 in Kirkland, Washington by former Microsoft employees Mike Harrington and Gabe Newell. Valve began working on the first game of the series soon after the company's formation, and settled on a concept for a horror-themed 3D action game, using the Quake engine as licensed by id Software. The game was a hit at the 1997 E3 convention, where its animation system and artificial intelligence were demonstrated. The game's success led to its first expansion pack, Half-Life: Opposing Force, which was developed by Gearbox Software, a then-new company based in Plano, Texas, and announced on April 15, 1999. Gearbox founder Randy Pitchford said in an interview that he believed Valve gave them the opportunity to produce a sequel to Half-Life to allow Valve to focus on future games. The game was demonstrated at the 1999 E3 convention, where new locations, characters, and the story were revealed.
The second Half-Life expansion pack, Half-Life: Blue Shift, was again developed by Gearbox Software and announced by its publisher, Sierra Entertainment, on August 30, 2000. Sierra intended to release Blue Shift for the Dreamcast, and it was set to include higher detail models and textures that were double the polygon count of the models from Half-Life. However, after several months of delays, Sierra terminated development on the Dreamcast version of Blue Shift on June 16, 2001, and the company instead released Blue Shift for the PC on June 12, 2001. Afterward, Gearbox began working on a Half-Life game for the PlayStation 2. The game, Decay, was showcased at E3 2001, where Gearbox demonstrated the game's use of new model sets, which were around twice as detailed as those in Blue Shift.
For several years, Valve secretly worked on the sequel to the original Half-Life, Half-Life 2. For the game, Valve developed a new game engine, Source, 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. In the trilogy of episodic games that followed Half-Life 2, Valve made minor tweaks to the game's engine. In Half-Life 2: Episode One, Valve modified Alyx's AI to allow her to react to the player's actions because of her significant involvement in the game. The game runs on an upgraded version of Valve's proprietary Source engine, and features both the engine's advanced lighting effects, and a new version of its facial animation/expression technology.
On February 6, 2013, while speaking at the 2013 DICE conference about storytelling in games and film, J. J. Abrams and Gabe Newell announced that they had plans for a game and a film collaboration. Abrams said, "There's an idea we have for a game that we'd like to work with Valve on," while Newell said, "We're going to figure out if we can make a Portal movie or Half-Life movie together". In an interview in March 2016, Abrams stated that while he has been working on many other projects since, he still has plans to direct these films in the future, with both films in the writing stage.
A short film, Half-Life: Uplink, was developed by Cruise Control, a British marketing agency, and released on March 15, 1999. However, Sierra withdrew it from circulation after Sierra and Valve had failed to resolve licensing issues with Cruise Control over the film. The critical reception of the film was very poor. The film's plot was that of a journalist attempting to infiltrate the Black Mesa Research Facility and discover what was happening there.
Half-Life: Escape from City 17Edit
In early 2009, the Purchase Brothers, a Toronto-based film company, released a five-minute film based on Half-Life 2: Episode One, Half-Life: Escape from City-17. The film combines live-action footage with 3D animation created using the Source SDK. It was well received by Valve. On August 25, 2010 they released a nearly 15-minute long sequel.
Beyond Black MesaEdit
In late 2010, a trailer for a Half-Life inspired independent short film, Beyond Black Mesa, was released. Directed by Brian Curtin, it follows the character Adrian Shephard. The full short film was released online on January 21, 2011.
In December 2008, Valve announced that the two main Half-Life games had sold 15.8 million units in retail (9.3m for the first, 6.5m for the second), while the Half-Life expansions had sold 1.9 million (Opposing Force: 1.1 million, Blue Shift: 800,000) and Half-Life 2 expansions 1.4 million (all for Episode One). Additionally, The Orange Box, which included Half-Life 2 and both of its episodic expansions, sold 3 million units at retail by that time. This put franchise sales at 18.8 million full games (Half-Life: 9.3m, Half-Life 2: 9.5m) and 9.3 million expansions (Opposing Force: 1.1m, Blue Shift: 0.8m, Episode One: 4.4m, Episode 2: 3.0m), as of December 2008. These figures did not account for digital sales. Half-Life: Counter-Strike sold 4.2 million units standalone by the same time, while its remake, Counter-Strike: Source was bundled with every sold retail copy of Half-Life 2. Forbes reported that, including digital sales, Half-Life 2 had sold over 12 million copies by February 2011.
- "Half-Life". IGN. Retrieved October 23, 2008.
- "Half-Life: Source for PC". GameSpot. Archived from the original on May 22, 2007. Retrieved May 26, 2009.
- "Half-Life Reviews (PC: 1998)". Metacritic. Retrieved May 26, 2009.
- "Awards and Honors". Valve. Retrieved November 14, 2005.
- Cifaldi, Frank (September 1, 2006). "The Gamasutra Quantum Leap Awards: First-Person Shooters". Gamasutra. Retrieved February 16, 2009.
- "IGN's Top 100 Games". IGN. July 25, 2005. Archived from the original on October 9, 2014. Retrieved February 19, 2009.
- "Half-Life: Opposing Force". Steam. Valve. Retrieved November 19, 2008.
- "Half-Life Expands". IGN. April 15, 1999. Retrieved November 18, 2008.
- "Half-Life: Opposing Force Reviews". GameRankings. Retrieved November 18, 2008.
- Wolpaw, Erik (November 24, 1999). "Half-Life: Opposing Force for PC Review". GameSpot. Retrieved November 20, 2008.
- Randell, Kim (August 15, 2001). "PC Review: Half-Life: Opposing Force". Computer and Video Games. Retrieved November 20, 2008.
- "Review: Half-Life: Opposing Force". GamePro. November 24, 2000. Archived from the original on December 29, 2008. Retrieved November 20, 2008.
- "AIAS Annual Awards: 3rd Annual Awards". Academy of Interactive Arts & Sciences. 2000. Archived from the original on February 20, 2009. Retrieved November 21, 2008.
- Kirchgasler, Chris (July 24, 2000). "Half-Life Preview". GameSpot. Retrieved March 31, 2016.
- Satterfield, Shane (June 16, 2001). "Half-Life for the Dreamcast officially cancelled". GameSpot. Retrieved October 26, 2008.
- "Half-Life: Blue Shift". IGN. Archived from the original on February 15, 2012. Retrieved October 26, 2008.
- "Half-Life: Blue Shift Q&A". GameSpot. May 3, 2001. Retrieved October 26, 2008.
- Blevins, Tal (June 12, 2001). "Half-Life: Blue Shift Review". IGN. Retrieved October 27, 2008.
- Madigan, Jamie. "Reviews: Half-Life: Blue Shift". GameSpy. Archived from the original on September 12, 2012. Retrieved October 27, 2008.
- Kasavin, Greg (June 8, 2001). "Half-Life: Blue Shift for PC Review". GameSpot. Retrieved October 27, 2008.
- "Half-Life". IGN. Retrieved October 23, 2008.
- Fielder, Joe (May 17, 2001). "E3 2001 Hands-on Half-Life". GameSpot. Retrieved October 23, 2008.
- Hodgson, David. "Reviews: Half-Life (PS2)". GameSpy. Archived from the original on July 9, 2008. Retrieved October 23, 2008.
- Smith, Steve. "Review: Half-Life". The Electric Playground. Archived from the original on October 3, 2008. Retrieved October 24, 2008.
- Radcliffe, Doug (October 15, 2001). "Half-Life for PlayStation 2 Review". GameSpot. Retrieved October 23, 2008.
- Meer, Alec (September 28, 2008). "Half-Life: The Lost Chapter". Rock, Paper, Shotgun. Retrieved October 24, 2008.
- "Half-Life: The Story so Far". Valve. Archived from the original on July 25, 2008. Retrieved March 24, 2008.
- Lee, Garnett (August 29, 2005). "Half-Life 2: Aftermath and Lost Coast". 1UP.com. Archived from the original on May 22, 2011. Retrieved November 20, 2008.
- Accrado, Sal (October 28, 2005). "Half-Life 2: The Lost Coast (PC)". GameSpy. Archived from the original on October 11, 2012. Retrieved October 17, 2008.
- "Half-Life 2: Lost Coast Allies". Planet Half-Life. GameSpy. Archived from the original on April 26, 2013. Retrieved November 21, 2008.
- "Half-Life 2: Episode One gold, Two dated, Three announced". GameSpot. May 24, 2006. Retrieved May 18, 2007.
- Bramwell, Tom (June 6, 2006). "Opening the Valve". Eurogamer. Retrieved August 28, 2017.
- "12 big things we learned about Half-Life: Alyx". PC Gamer. November 21, 2019. Archived from the original on November 23, 2019.
- "Half-Life: Alyx for PC Reviews - Metacritic". Metacritic. Retrieved March 24, 2020.
- McKeand, Kirk (March 23, 2020). "Half-Life: Alyx review - VR's killer app is a key component in the Half-Life story". VG247. Retrieved March 24, 2020.
- Carbotte, Kevin. "Half-Life: Alyx Gameplay Review: (Almost) Every VR Headset Tested". Tom's Hardware. Retrieved March 24, 2020.
- Robinson, Andrew (March 23, 2020). "Review: Half-Life Alyx is VR's stunning killer app". VGC. Retrieved March 24, 2020.
- Ted Backman; Jeremy Bennett; Tristan Reidford (July 9, 2008). "Advisor". Into the Pixel. Retrieved July 14, 2008.
- Decker, Logan (July 10, 2008). "The first concept art from Half-Life 2: Episode Three". PC Gamer. Retrieved July 14, 2008.
- Chris_D (June 27, 2012). "EXCLUSIVE: Half-Life 2: Episode 3 Concept Art". ValveTime. Archived from the original on August 6, 2012. Retrieved July 29, 2013.
- McWhertor, Michael (August 7, 2009). "Valve Studying Sign Language For Deaf Half-Life Character". Kotaku. Retrieved August 23, 2009.
- Yoon, Andrew (August 7, 2009). "Valve researching sign language for use in Half-Life 2: Episode 3". engadget. Retrieved March 31, 2009.
- Reilly, Jim (August 10, 2009). "Valve Studying Sign Language for Episode 3?". IGN. Retrieved March 31, 2016.
- "Whatever happened to Half-Life 3? The complete saga so far". PCGamesN. August 25, 2017. Retrieved August 28, 2017.
- Brian Warmoth (March 26, 2010). "Valve Wants Their Next 'Half-Life' To Scare You". Archived from the original on March 29, 2010. Retrieved March 28, 2010.
- Rob Crossley (May 9, 2011). "The Valve manifesto".
- Calore, Michael (January 3, 2011). "Vaporware 2010: The Great White Duke". Wired.com. Retrieved July 30, 2013.
- Marks, Tom (March 23, 2020). "Valve Explains Why Half-Life 2: Episode 3 Was Never Made". IGN. Retrieved March 23, 2020.
- Souppouris, Aaron (May 2, 2017). "Valve has no more 'Half-Life' writers left". Engadget. Retrieved August 28, 2017.
- "Marc Laidlaw (Valve) - Interview". Arcade Attack. July 17, 2017. Retrieved November 23, 2019.
- "The world's most anticipated game may never come out — so its writer leaked the story". Business Insider. Retrieved August 26, 2017.
- Robertson, Adi (August 25, 2017). "Marc Laidlaw's coded Half-Life 'fanfic' is probably the closest we'll get to Half-Life 3". The Verge. Retrieved August 26, 2017.
- McWhertor, Michael (August 28, 2017). "Steam users are attacking Dota 2 because there's no more Half-Life". Polygon. Retrieved August 28, 2017.
- Bailey, Dustin (October 4, 2017). "Project Borealis aims to bring Half-Life 2: Episode 3 to life in Unreal". PCGamesN. Retrieved December 28, 2017.
- England, Rachel (December 28, 2017). "'Half-Life 3' fan venture 'Project Borealis' is taking shape". Engadget. Retrieved December 28, 2017.
- Peel, Jeremy (November 19, 2018). "Half-Life 3 is now in the hands of its community, in the form of Project Borealis". PCGamesN. Retrieved November 19, 2018.
- "Why Valve Gave Up On 'Multiple' Half-Life 3s". Kotaku. Retrieved March 26, 2020.
- Scott-Jones, Richard (March 27, 2017). "Ravenholm features in another cancelled Half-Life 2 episode, now with snow and magnetism". PCGamesN. Retrieved March 27, 2017.
- Benson, Julian (September 20, 2017). "Warren Spector reveals how the magnet gun would have worked in cancelled Half-Life episode". PCGamesN. Retrieved September 20, 2017.
- Turi, Tim (April 24, 2015). "Abandoned Half-Life Episode Featured Magnet Gun, Warren Spector Says". Retrieved May 19, 2015.
- Lane, Rick (November 8, 2017). "Warren Spector discusses his cancelled Half-Life 2 Ravenholm Episode". PC Gamer. Retrieved November 8, 2017.
- The Untold History of Arkane: Dishonored / Prey / Ravenholm / LMNO / The Crossing. Noclip. May 26, 2020. Event occurs at 33:00. Retrieved May 26, 2020 – via YouTube.
- "Marc Laidlaw On The Cancelled Half-Life Spin-offs: Return To Ravenholm And "Episode Four"". LambdaGeneration. January 13, 2012. Archived from the original on January 16, 2012. Retrieved July 19, 2013.
- Savage, Phil (January 15, 2013). "Half-Life 2: Episode 4 was being developed by Arkane; now cancelled". PC Gamer. Retrieved July 8, 2014.
- McLeand, Kirk (December 5, 2015). "Half-Life 2: Episode Four - Return to Ravenholm forgotten screens surface". PCGamesN. Retrieved March 27, 2017.
- "Counter-Strike 1.6 Beta released". Steam. January 28, 2013. Archived from the original on February 14, 2013. Retrieved March 16, 2014.
- Remo, Chris (December 3, 2008). "Analysis: Valve's Lifetime Retail Sales For Half-Life, Counter-Strike Franchises". Gamasutra. Retrieved October 24, 2018.
- Half-Life Platinum Collection. sierrachest.com. Retrieved March 2, 2019.
- Thorsen, Tor. "Valve readying Half-Life 2 bundles; Counter-Strike: Source available next week." Gamespot. September 29, 2004
- Autrijve, Rainier Van (October 6, 2004). "Blow Off Some Steam and Pre-Order Half-Life 2 (PC)". GameSpy. Archived from the original on October 6, 2008. Retrieved October 3, 2008.
- Nathan Grayson. "Portal Easter Egg In Counter-Strike Isn't Teasing A New Game, Valve Says." Kotaku. December 12, 2018.
- Cliffe, Jess (May 18, 2004). "CODENAME GORDON RELEASED". Steam.
- Doomer, Ivan. "Free Steam games list". Steam User's Forums. Archived from the original on May 17, 2009. Retrieved October 1, 2009.
- Senior, Tom (September 3, 2012). "Black Mesa Source release date revealed, high-res headcrabs due in 11 days". PC Gamer. Future Publishing Limited. Archived from the original on September 22, 2012. Retrieved September 22, 2012.
- Cobbett, Richard (September 14, 2012). "Black Mesa Source released – download it now!". PC Gamer. Future Publishing Limited. Archived from the original on September 25, 2012. Retrieved September 22, 2012.
- Hillier, Brenna (January 3, 2016). "At 10 million sales, Garry's Mod is still going strong". VG247. Retrieved January 3, 2016.
- "Minerva". Idle Thumbs. November 16, 2006. Retrieved April 30, 2006.
- Keighley, Geoffrey. "The Final Hours of Half-Life". GameSpot. Archived from the original on January 16, 1999. Retrieved December 17, 2008.
- "Half-Life Expands". IGN. April 15, 1999. Retrieved December 17, 2008.
- "Half-Life: Opposing Force interview". Computer and Video Games. August 15, 2001. Retrieved December 17, 2008.
- "Half-Life: Opposing Force". IGN. May 25, 1999. Retrieved December 18, 2008.
- Trueman, Doug (August 29, 2000). "DC Half-Life Includes Blue Shift". GameSpot. Retrieved December 18, 2008.
- Stahl, Ben (September 5, 2000). "ECTS Half-Life Dreamcast Hands-On". GameSpot. Retrieved October 26, 2008.
- "ECTS 2000: Hands-On With Half-Life". IGN. August 1, 2000. Retrieved October 26, 2008.
- "Half-Life Preview". IGN. September 19, 2001. Retrieved October 23, 2008.
- Ajami, Amer (September 11, 2001). "Half-Life Updated preview". GameSpot. Archived from the original on January 3, 2013. Retrieved October 23, 2008.
- Fudge, James (March 25, 2004). "Havok's Half-Life 2 Marketing Campaign". GameSpy. Retrieved September 23, 2008.
- Half-Life 2: Episode One, Chapter V: Exit 17, Developers commentary (DVD). 2006.
- Bramwell, Tom (June 6, 2006). "Opening the Valve". Eurogamer. Retrieved April 29, 2007.
- "Valve working with J.J. Abrams' Bad Robot on game and movie collaborations".
- "Portal, the Movie: Valve, J.J. Abrams Team Up for Future Games, Films". Wired. February 6, 2013.
- Strom, Steven (March 12, 2016). "J.J. ABRAMS: PORTAL, HALF-LIFE MOVIES STILL HAPPENING". IGN. Retrieved March 12, 2016.
- "Half-Life: Uplink Movie". Blue's News. February 17, 1999. Retrieved December 16, 2006.
- "Half-Life: Uplink — Page 1". Planet Half-Life. March 15, 1999. Archived from the original on September 25, 2011. Retrieved December 16, 2006.
- "Editors Note: Uplink Movie". Planet Half-Life. March 15, 1999. Archived from the original on May 4, 2009. Retrieved December 16, 2006.
- Brown, Michael (February 17, 1999). "Half-Life: The Movie". CNET. Archived from the original on May 31, 2000. Retrieved December 16, 2006.
- Walker, John (February 13, 2009). "Escape From City 17: Part One". Rock, Paper Shotgun. Retrieved February 17, 2009.
- "Escape From City 17: Part One". Valve. February 13, 2009. Retrieved May 15, 2010.
- Wallace, Lewis (November 11, 2010). "Trailer: Indie Sci-Fi Short Beyond Black Mesa Channels Half-Life". Wired. Condé Nast Publications. Retrieved November 17, 2010.
- Independent of Half-Life: Decay, which was bundled with the retail sales of the PlayStation 2 version of Half-Life.
- Chris Remo. Analysis: Valve's Lifetime Retail Sales For Half-Life, Counter-Strike Franchises Exclusive. Gamasutra. December 3, 2008.
- Chiang, Oliver, "The Master of Online Mayhem." Forbes. February 9, 2011.