Originally published as a free mod in September 2012, Black Mesa was approved for commercial release by Valve, the developers of Half-Life.

The team originally targeted a 2009 release, but realized they had rushed to this point and reevaluated their efforts to improve the quality of the remake.

Adapting the game to an improved version of the Source engine and completely reworking the often-derided final chapter of Half-Life (known as Xen) had lengthened the development efforts of the remake.

Major changes include reskinned collection of textures, models and NPCs, a longer runtime, altered level and puzzle design along with different enemy artificial intelligence, and additional dialogue and story elements.

Black Mesa received positive reviews, with critics praising the gameplay and attention to detail akin to that of an official Valve release.

Black Mesa is a first-person shooter that requires the player to perform combat tasks and solve various puzzles to advance through the game.

[1] Black Mesa also includes support for the individual and Team Deathmatch multiplayer modes from Half-Life on similarly updated maps.

[3] Like in the original game, the player controls Gordon Freeman, a theoretical physicist working at the Black Mesa Research Facility.

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.

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.

[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.

[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.

This new version included more advanced particle effects, hardware-accelerated facial animation, and support for multi-core processor rendering, amongst other improvements.

[18] The development team estimated that the initial release of Black Mesa gave players eight to ten hours of content to complete.

[20] Crowbar Collective continued to offer the free version of Black Mesa, based on the earlier Source engine, on their website.

[22] Early access also brought Crowbar Collective additional support from developers and artists to help with finalizing the project.

[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.

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 made redesigns in some of these levels.

[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.

"[40] With the transition from mod to game in 2015, Jansen returned to the idea and started work on recreating it for the Steam version that featured new content and updated graphics called Black Mesa: Uplink Redux.

[50] On February 16, 2021, the HECU Collective announced that they would be taking a break from their mod Black Mesa: Azure Sheep and were now focusing on a remake of Half-Life: Blue Shift.

[51][52] Unlike another remake in progress, Guard Duty by Tripmine Studios, the mod utilizes assets from Black Mesa instead of creating it from scratch and is released in chapters.

Valve published a news update about the modification on their Steam digital distribution platform in 2007 saying that "We're as eager to play [Black Mesa] here as everyone else.

[68] After receiving a development version of Black Mesa in December 2009, PC PowerPlay magazine said that the game's setting "looks, sounds, [and] plays better than ever before".

[74] Eurogamer said that Black Mesa felt more like an evolution than a remake of Half-Life, with the designs of the Crowbar Collective to trim down certain levels while adding other features helped to enhance the overall product, making the overall title more of a survival horror than a first-person shooter.