Black Mesa is a 2020 first-person shooter game developed and published by Crowbar Collective. It is a third-party remake of Half-Life (1998) made in the Source game engine. Originally published as a free mod in September 2012, Black Mesa was approved by Half-Life developers Valve for a commercial release; the first commercial version was published as an early-access version in May 2015, followed by a full release in March 2020 for Microsoft Windows and Linux.

Black Mesa was developed in response to Half-Life: Source (2005), Valve's port of Half-Life to the Source engine, which lacked new features or improvements. Two teams wanted to improve on the Source remake and eventually merged to become Crowbar Collective. While they had originally targeted a release by 2009, the team realized they had rushed to this point and reevaluated their efforts to improve the quality of the remake.

Since then, attention to details, adapting the game to an improved version of the Source engine, and completely reworking the oft-derided final chapters of Half-Life (known as Xen) had lengthened the development efforts of the remake. Due to its long development time, the modification became notable for its delays on the status of its completion. Major changes include reskinned collection of textures, models and NPCs, a longer runtime, improved level and puzzle design along with challenging enemy artificial intelligence, and additional dialogue and story elements.

The early-access version of Black Mesa received positive reviews and gained more positive reviews as it was updated and improved. Reviewers praised the gameplay and attention to detail, comparing it to that of an official Valve release, and the improvements to the Xen chapters.

Gameplay
See also: Half-Life (video game) § Gameplay

Comparison of the Anomalous Materials lobby room in Half-Life (top) and Black Mesa (bottom)
Black Mesa is a first-person shooter that requires the player to perform combat tasks and solve various puzzles to advance through the game. From a design standpoint, the core gameplay remains largely unchanged from the original base Half-Life game; the player can carry a number of weapons that they find through the course of the game, though they must also locate and monitor ammunition for most weapons. The player's character is protected by a hazard suit that monitors the player's health and can be charged as a shield, absorbing a limited amount of damage. Health and battery packs can be found scattered through the game, as well as stations that can recharge either health or suit charge.

However, unlike Half-Life: Source, which merely featured the original game's assets and geometry ported to the Source engine, Black Mesa has been purpose-built from the ground up to take full advantage of the newest versions of Source, not just for its graphical capabilities, but for its myriad updates to the game's physics engine, puzzle complexity, and platforming capability. The artificial intelligence of the enemy characters has also been improved over Half-Life to provide more of a challenge, with some of the combat spaces redefined to provide more options to the player.[1][2] In addition, several narrative and design changes have been made to account for the numerous story threads presented via retcon in Half-Life 2. While most of the general design and progress through the game levels remains the same as Half-Life, the largest change in Black Mesa is the reworking of the game's final chapter, Xen, which was generally considered the weakest part of the original game.[1]

Black Mesa also includes support for the individual and team deathmatch multiplayer modes from Half-Life on similarly-updated maps.[2]

Plot
See also: Half-Life (video game) § Plot
The plot of Black Mesa is almost identical to Half-Life's storyline.[3] Like in the original game, the player controls Gordon Freeman, a theoretical physicist working at the Black Mesa Research Facility. He is tasked to place a sample of anomalous material into an Anti-Mass Spectrometer for analysis, using the Mark IV Hazardous Environment Suit (HEV Suit) to do so safely. However, the sample causes a "resonance cascade", devastating the facility and creating an interdimensional rift to an alien dimension called Xen, bringing its alien creatures to Earth. Freeman survives the incident, finds other survivors, and is tasked to make his way to the surface to call for help. Upon reaching the surface, however, he finds that the facility is being cleansed of any living thing - human or alien - by the military. Freeman learns from the surviving scientists the only way to stop the alien invasion is to cross over to Xen and destroy the entity keeping the rift open.

Development
See also: List of video games derived from mods
Initial efforts (2005–2012)

The "Surface Tension" chapter as it appears in Half-Life

The same scene in a development version of Black Mesa
With the release of Half-Life 2 in 2004, Valve re-released several of its previous titles, ported to their new Source game engine, including the critically acclaimed 1998 game Half-Life as Half-Life: Source. The Source engine is graphically more advanced than the GoldSrc engine used for the original games. Half-Life: Source features the Havok physics engine and improved effects for water and lighting. The level architecture, textures, and models of the game, however, remained unchanged. Half-Life: Source was met with mixed reviews. IGN liked the new user interface and other technical features, but noted that it did not receive as many improvements as Valve's other Source engine ports.[4] GameSpy said that while it was a "fun little bonus", it was "certainly not the major graphical upgrade some people thought it might be".[5] Valve's managing director Gabe Newell is quoted as saying that a complete Source remake of Half-Life by its fans was "not only possible…but inevitable".[6]

Black Mesa began as the combination of two independent volunteer projects, each aiming to completely recreate Half-Life using Source. The Leakfree modification was announced in September 2004. The Half-Life: Source Overhaul Project was announced one month later.[7] After realizing their similar goals, project leaders for both teams decided to combine their efforts; they formed a new 13-person team under the name Black Mesa: Source.[6] The "Source" in the project's title was later dropped when Valve asked the team to remove it in order to "stem confusion over whether or not [it was] an endorsed or official product", which at the time it was not.[8] Eventually, the team rebranded itself as the Crowbar Collective. Most of the team was distributed across the world and used online collaboration to work remotely, with some limited in-person meetings.[7]

Originally based on the version of Source released with Counter-Strike: Source in 2004, the project switched to a more recent version released with Valve's The Orange Box in 2007. This new version included more advanced particle effects, hardware-accelerated facial animation, and support for multi-core processor rendering, amongst other improvements.[9][10][11] The team had expected this to be a relatively fast project, with trailers released in 2005 and 2008, and an initial release estimate of late 2009, but by mid-2009, had backed off that date, and changed their expected release date to "when it's done".[12] Wired included the game on their "Vaporware of the Year" lists in 2009 and 2010.[13][14] In the lead-up to the 2012 release, team member Carlos Montero said that in 2009 that they thought they were going to be able to make that date, but "ended up busting our asses to make that a reality, and we went against a lot of our core values in the process. We found ourselves rushing things, cutting things, making quality sacrifices we did not want to make."[15] Montero said then they decided to re-evaluate the state of the project, set higher bars for

the quality of work they wanted to produce, and started to back through what they had already done to improve upon that, at which point they were not sure when the project would be completed.[15]

The first standalone version of Black Mesa was released as a free download on September 14, 2012.[16][17] This contained remakes of all Half-Life's chapters except the final chapter set on the alien world Xen, which the team intended to rework for inclusion in a future release, as Xen in the original Half-Life was often considered its weakest part.[18] The development team estimated that the initial release of Black Mesa gave players eight to ten hours of content to complete.[18] Black Mesa's initial release coincided with the launch of Valve's Steam Greenlight program which allowed users to vote for games to be put onto the Steam storefront. Black Mesa became one of the first ten titles to be voted on by fans and approved by Valve to be included on Steam through Greenlight.[19]

Transitioning to commercial release (2013–2014)
A new version of the Source engine had been introduced by 2013 that, in addition to new engine features, included support for OS X and Linux platforms, however, developers had to pay to gain access to the full feature set of this engine. According to Adam Engels, the project lead at the completion of Black Mesa, Valve had actually approached their team around this time and suggested to them about making Black Mesa a commercial release and thus getting a license to the Source engine.[7] The team considered this option, and since access to the full Source engine would help make Black Mesa the best game they could, they opted to go the commercial route as to be able to pay for that license, not having intended to profit off the game from the start.[20] The team affirmed they had gotten Valve's permission to sell by November 2013.[20] Some of the team were later invited to Valve's offices in Bellevue, Washington in 2015.[7]

At this point in 2013, the team cautioned that a final version was still some distance away as they were still dealing with the updated Source engine, and they had not yet done much with Xen.[20] Crowbar Collective continued to offer the free version of Black Mesa based on the earlier Source engine off their website.[20] With the new Source engine, the team started to look closer at how Valve had used Source in Half-Life 2 compared to what they had done in the original Half-Life, and developed changes for Black Mesa that reflected what they believed were Valve's design principles in Half-Life 2. One of those was the idea that when introducing a new mechanic, the level was designed to teach the new mechanic without potential harm to the player-character, followed by then testing that mechanic in a more harmful situation to the character.[21] The team also included a brief mention to the long-fall boots from Aperture Science from the Portal series; Portal had come out after Half-Life 2 but loosely tied narratively to the Half-Life universe, and the team felt it appropriate to show the competing lab's technology within the Black Mesa facility from this connection.[21]

Once the team had gotten all but the Xen levels completed in the new Source engine they were content with, they released these on Steam's early access on May 5, 2015, to get feedback and bug testing, stating that the Xen sections were still a work in progress. This version also included the deathmatch multiplayer modes with some of Half-Life's remade maps.[22] Early access also brought Crowbar Collective additional support from developers and artists to help with finalizing the project.[7]

Xen and final release (2015–2020)
The release of the Xen part of the game had been the most difficult, since the team wanted to redesign the levels to overcome the poor perception that they had in Half-Life's original release. The team said, "We want our version of Xen to feel like it really belongs with the rest of the game in terms of mechanics, cohesion and progression," while at the same time, they wanted "to push the boundaries and explore this unique and varied setting; to build an experience that feels both fresh and familiar to players from all walks of Half-Life veterancy."[23] Developing their new version of Xen was a chicken-or-the-egg dilemma, as without level design it was difficult to develop art assets, and without art assets it was hard to come up with cohesive level designs.[2] They also wanted to give more story elements there, such as why human scientists were studying the world of Xen in the first place, trying to capture the same type of world-building by level design that Valve had been able to with the first parts of Half-Life.[7] They also significantly reworked the boss battles to be more challenging and representative of the area they had in mind.[2] Ultimately, the team expanded out Xen from about a one-hour experience in the original Half-Life to four hours in Black Mesa.[2]

In addition to reworking Xen from scratch, as the team members got closer to release, they recognized they saw the game more as an entry for new players into the Half-Life series, and worked to introduce designs and features that would be more appropriate a decade since Half-Life's release. They made combat more interesting by improving the enemy's artificial intelligence while creating combat areas with more cover and options for the player. Because of their expansion of Xen, they also wanted to make sure players were not slowed down in the earlier parts of the game, and make redesigns in some of these levels.[2]

The release of Xen in the early access version of Black Mesa had been pushed off a few times; initially planned for a December 2017 release,[24][25][26] a beta version of a segment of the remade Xen was released in June 2019 for stress-testing by players[27] The full beta was released on December 6, 2019.[28] Additional Xen levels were added over time, and by December 24, 2019, the full Xen chapter was released as part of the game's early access.[29]

The finished Black Mesa was released for Windows on March 6, 2020.[30] By chance, this release was about two weeks before Valve's official return to the Half-Life universe after 13 years with the virtual reality game Half-Life: Alyx. Black Mesa project lead Adam Engels said this was not intentional as they had planned to have Black Mesa out earlier, but the attention to Alyx had helped to boost interest in Black Mesa.[2] In addition to ongoing support for the game before moving onto other projects, the Crowbar Collective has stated they have been contacted by other teams, such as the Sven Co-op team, to help integrate their work into the final Black Mesa product.[2] The team also wants to incorporate support for the Steam Workshop so that other players can add their own mods to the game.[31]

In addition to the modification itself, the game's thematic score, produced by sound designer Joel Nielsen, was independently released as a soundtrack in 2012.[32] Nielsen released the score for the Xen levels in 2019.[33]

Definitive Edition
Following the first release of Black Mesa, the team announced work on a Definitive Edition, or Black Mesa 1.5, revamping non-Xen levels from the original Valve design to make them more challenging, as well as to take advantage of new lighting features available in the custom Source engine branch the game uses.[34] This free update was released on November 25, 2020.[35]

Modifications
As Black Mesa is built on the Source engine, it itself is also moddable with support for Steam Workshop, and several projects have been started to create versions of Half-Life mods and expansions within Black Mesa.

Xen Museum
The Crowbar Collective released an expansion in April 2021 called Xen Museum that presents a virtual museum that documents the team's past five years of effort in creating Black Mesa and mostly their work in recreating Xen from the original Half-Lif