Question: When was the Half-Life first-person shooter game released by game development community MapCore? 

full_context: Document 1: Half-Life: Blue Shift: Half-Life: Blue Shift is an expansion pack for Valve Software's science fiction first-person shooter video game "Half-Life". The game was developed by Gearbox Software with Valve Corporation and published by Sierra Entertainment on June 12, 2001. "Blue Shift" is the second expansion for "Half-Life", originally intended as part of a Dreamcast version of the original game. Although the Dreamcast port was later cancelled, the PC version continued development and was released as a standalone product. The game was released on Steam on August 24, 2005.
Document 2: Half-Life 2: Episode One: Half-Life 2: Episode One is a first-person shooter video game, the first in a series of episodes that serve as the sequel to the 2004 "Half-Life 2". It was developed by Valve Corporation and released on June 1, 2006. Originally called "Half-Life 2: Aftermath", the game was later renamed to "Episode One" after Valve became confident in using an episodic structure for the game. Similar to "Half-Life 2", "Episode One" also uses the Source game engine. The game debuted new lighting and animation technologies, as well as AI sidekick enhancements.
Document 3: Montreal International Games Summit: The Montreal International Games Summit (MIGS), also known as le Sommet International du jeu de Montréal (SIJM), is a conference on video games. The first edition was held in 2004 and usually takes place in November at le Palais des Congrès de Montréal. The summit was founded in order to meet the needs of the rough 9000 video game workers in Quebec. The mission of the summit is to expand the exposure of the video game community and industry in Quebec as well as develop the expertise of the Quebec video game industry. MIGS is currently the leading professional gaming summit of the East Coast, and is arguably the largest game development event in Canada. The overall aims of MIGS are to promote, train, network, and hire potential players in the gaming industry. Professionals attending the summit partake in lectures and presentations largely oriented around how to better specific aspects of the industry, such as art and VFX, business, and design. Currently, MIGS has partnered with many of the leading electronic and game development companies in Canada, including Ubisoft and Warner Bros. Games. The Montreal International Gaming Summit is networked similarly to the Electronic Entertainment Expo, using the same application in order to facilitate interaction between industry players and their associates. It was only in 2008, during the fifth summit, did MIGS become an event that was open to the public. 2013 marked the tenth annual Montreal International Gaming Summit.
Document 4: Video game development: Video game development is the process of creating a video game. The effort is undertaken by a game developer, which may range from a single person to an international team strewn across the globe. Traditional commercial PC and console games are normally funded by a publisher, and can take several years to reach completion. Indie games can take less time and can be produced at a lower cost by individuals and smaller developers. The independent game industry has seen a substantial rise in recent years with the growth of new online distribution systems, such as Steam and Uplay, as well as the mobile game market, such as for Android and iOS devices.
Document 5: Nexus Mods: Nexus Mods is a gaming fan site which allows users to upload their own created content, termed "modifications" or "mods", for various games. It is one of the largest gaming modification websites on the web, with 10 million registered members as of November 2015. Founded in 2001 as a fan site, it was modified into the website TEESsource in 2007. The Nexus Mods network supported 206 games as of October 2015, with a single forum and a wiki for site and mod-related topics. Recently, the Nexus Mods site expanded to serve as a host for mod files for any modifiable PC game. The website's hosting and publication of various mods has been covered in the gaming and computer press.
Document 6: Half-Life 2: Deathmatch: Half-Life 2: Deathmatch is a multiplayer first-person shooter video game developed by Valve Corporation. Released on Steam on November 30, 2004, it uses many of the assets from "Half-Life 2" and its Source engine. It features new levels, optimized for multiplayer arena play, and a few new weapons. Also included are portions of the game's source code, which were the basis for many early Source-based multiplayer modifications. The game is the successor to the popular multiplayer component of the original "Half-Life", but is offered as a separate product from "Half-Life 2". "Deathmatch", like "Half-Life"' s multiplayer, does not develop any part of the plot or story of the "Half-Life" series.
Document 7: Halo: Combat Evolved: Halo: Combat Evolved is a 2001 military science fiction first-person shooter video game developed by Bungie and published by Microsoft Game Studios. The first game of the "Halo" franchise, it was released as a launch title for the Xbox gaming system on November 15, 2001, and is considered the platform's "killer app". More than five million copies were sold worldwide by November 2005. Microsoft released versions of the game for Microsoft Windows and Mac OS X in 2003, and the surrounding storyline was adapted and elaborated into a series of novels, comic books, and live-action web series. The game was later released as a downloadable Xbox Original for the Xbox 360. A high-definition remake, "", was released for Xbox 360 on the 10th anniversary of the original game's launch, and was rereleased as part of "" on November 11, 2014, for the Xbox One.
Document 8: Half-Life: Opposing Force: Half-Life: Opposing Force is an expansion pack for Valve Software's science fiction first-person shooter video game "Half-Life". The game was developed by Gearbox Software and Valve Corporation and published by Sierra Entertainment on November 19, 1999. "Opposing Force" is the first expansion for "Half-Life" and was first announced in April 1999. Randy Pitchford, the lead designer on the game, later noted that he believed Gearbox was selected to develop "Opposing Force" because Valve wanted to concentrate on their future projects. Over the course of development, Gearbox brought in a variety of outside talent from other areas of the video games industry to help bolster various aspects of design.
Document 9: Jamil Moledina: Jamil Moledina works in the videogame industry doing business development. He was born in Mombasa, Kenya, raised in London and Los Angeles, and now lives in San Francisco. He works at Google as the Games Strategic Lead for Google Play, managing games curation strategy for key partners on the default Android store, as well as curating the games portfolio for Daydream, Google's VR platform. He was previously the CEO of Wormhole Games, the makers of "Tank Nation." Prior to that he was VP Business Development for Funzio, the makers of "Crime City,", through their acquisition by GREE. Moledina previously directed business development at the EA Partners studio of Electronic Arts, where he created and managed the EA Arthouse initiative to sign and publish indie downloadable games such as "Shank" and "DeathSpank." He also served on the Board of Directors of the International Game Developers Association, the professional association of the game industry.
Document 10: List of Valve Corporation video games: Valve Corporation is an American video game developer and publisher founded in 1996 by Gabe Newell and Mike Harrington. The company is currently based in Bellevue, Washington. Valve's first game was "Half-Life", a first-person shooter released in 1998. It received universal acclaim and sold over 9 million units in retail. Alongside "Half-Life"' s launch, Valve released development tools to enable the player community to create content and mods. The company then proceeded to hire the creators of popular mods, such as "Counter-Strike", which became the most popular multiplayer first-person shooter for the next decade.
Document 11: Half-Life: Decay: Half-Life: Decay is a multiplayer-only expansion pack for Valve Software's first-person shooter "Half-Life". Developed by Gearbox Software and published by Sierra Entertainment, "Decay" was released as part of the PlayStation 2 version of "Half-Life" in 2001. It is the third expansion pack for "Half-Life", and like its predecessors, "Decay" returns to the setting and timeline of the original story, albeit portraying the story from the viewpoint of a different set of protagonists: two women scientists working in the Black Mesa Research Facility. "Decay" is a cooperative multiplayer game, designed to be played by two people working together to pass through the game's levels.
Document 12: MapCore: MapCore is a game development community with origins in "Half-Life" mod production, which since its inception in 1999 has evolved into a thriving forum featuring all flavours of game development including level design, modelling, concept art, and programming. With 100+ members part of the professional games industry working for the likes of Blizzard, Crytek, DICE, Gearbox Software, Rockstar Games, and Ubisoft, MapCore offers an opportunity for professionals and amateurs alike to socialise, learn, teach, and find talent.
Document 13: Game art design: Game art design is a subset of game development. It is the process of creating the artistic aspects for video games. Video game art design begins in the pre-production phase of creating a video game. The video game artists are visual artists involved from the conception of the game and they make rough sketches of the characters, setting, objects, etc. These starting concept designs can also be created by the game designers before the game is moved into actualization. Sometimes these are concept designs are called “programmer art”. After the rough sketches are completed and the game is ready to be moved forward those artists or more artists are brought in to bring these sketches to life through graphic design.
Document 14: Half-Life (video game): Half-Life (stylized as HλLF-LIFE) is a science fiction first-person shooter video game developed by Valve, released in 1998 by Sierra Studios for Microsoft Windows. It was Valve's debut product and the first in the "Half-Life" series. Players assume the role of Dr. Gordon Freeman, who must fight his way out of a secret research facility after a teleportation experiment goes disastrously wrong, fighting enemies and solving puzzles.
Document 15: Video game developer: A video game developer is a software developer that specializes in video game development – the process and related disciplines of creating video games. A game developer can range from one person who undertakes all tasks to a large business with employee responsibilities split between individual disciplines, such as programming, design, art, testing, etc. Most game development companies have video game publisher financial and usually marketing support. Self-funded developers are known as independent or indie developers and usually make indie games.
ground_truth: 1998