Turtle Rock Studios (known as Valve South between 2008 and 2010) is an American video game developer founded in March 2002 by Mike Booth.

Turtle Rock Studios is involved in the creation of original titles as well as the provision of consulting services to the digital entertainment industry.

Prior to the company's establishment, Booth, Phil Robb and Chris Ashton worked for Westwood Pacific[3] and participated in the development of real-time strategy games like Command & Conquer: Red Alert 2.

Robb and Booth remained at Westwood Studios and worked on Command & Conquer: Yuri's Revenge and Command & Conquer: Generals, but left the company after it was acquired by Electronic Arts, as Robb considered EA's acquisition of Westwood had resulted in the studio losing all its personality.

[9] The team decided to use source code from Counter-Strike to develop a mod called Terror-Strike,[10] which is a scenario where players fight against bots, which are equipped only with knives and act like zombies.

On January 10, 2008, before the release of Left 4 Dead, Valve announced that it had purchased Turtle Rock in an effort to expand the company's console market.

Gabe Newell, founder and president of Valve, added that it was an easy decision for the company to make, as they had high expectations for Left 4 Dead and considered themselves having a long-term relationship with Turtle Rock.

[5] Valve retained the rights to the Left 4 Dead franchise, while allowing the name "Turtle Rock" and its logo to be used again by the original team.

[12] After being formally closed, the remaining team members including Ashton and Robb decided to restart Turtle Rock as an independent company[15] on March 17, 2010.

[16] On the same day, Turtle Rock Studios put up a new website announcing they had reformed and were once again working on video games.

They released an iPhone automotive maintenance app named Garage Buddy and began hiring for a full-scale project.

[19] On September 22, 2010, Digital Development Management announced they were representing Turtle Rock Studios to find publishers for their games.

THQ's then president Danny Bilson and Jason Rubin were very enthusiastic about the idea of having an asymmetrical multiplayer game like Evolve.

[5] The company's founders felt frustrated, and Rubin later suggested that Turtle Rock bid $250,000 for its own project, which Ashton described as "what [they] had in the bank".

[5] However, they were outbid by Take-Two Interactive, which paid $11 million to acquire the game and to secure the rights to the entire franchise.

[32] The PC version briefly transitioned to become a free-to-play title, but 2K ultimately decided to end the game's support.

[33] In December 2016, Turtle Rock announced that the company was working on a new intellectual property to be published by Perfect World Entertainment.

[34][35] The studio would also consider releasing titles via Steam's early access program, which allows players to provide feedback on unfinished games or products as they are being developed.

[37] The studio experimented with several virtual reality titles, while working with Warner Bros. Interactive Entertainment on Back 4 Blood, a new zombie co-op FPS in the vein of Left 4 Dead, which released for Windows, PlayStation 4, PlayStation 5, Xbox One and Xbox Series X/S on October 12, 2021.

[38] Slamfire Inc., the parent company of Turtle Rock Studios, was acquired by Tencent in December 2021 for undisclosed terms.

Works include: Left 4 Dead is a first-person shooter survival horror video game released in November 2008 for Microsoft Windows and Xbox 360.

While the game received generally positive reviews,[50] its extensive list of downloadable content available at launch caused controversy.

Though inspired by Valve's Left 4 Dead games, Back 4 Blood is a wholly original intellectual property, though still sees players working cooperatively to fight through a zombie apocalypse.