Gunman Chronicles or Half-Life: Gunman (previously Gunman: TC and simply Gunman) is a first-person shooter space western video game originally created as a mod by the now defunct Rewolf Software. Gunman Chronicles was originally a Quake deathmatch mod named Gunmanship 101, then it was moved to Quake II's engine before becoming a Half-Life mod. At the Half-Life Mod Expo in 1999, Gunman Chronicles stole the show and Sierra approached Rewolf to make a retail version. After significant work, Rewolf was given some office space, funding and a mapper (Jeff Lane) by Valve Software to help complete the project. It was released as a standalone game.

Gunman Chronicles, taking place at an unknown time in the distant future, contains many themes, most notably the design focuses on Science Fiction, Cyberpunk, Steampunk, Futuristic and Western. While the game takes advantage of these in many instances, it still has a wide variety of influences. The Gunmen's Federal Starbase, Aeronautica, and the Facility at the Ferrin Moon harbor a vast collection of Techno-Futuristic and Cyberpunk themes and architecture, although they also seem to contain many designs, most notably textures and architecture, that bear striking resemblance in appearance to some of the works of the Swiss artist; H.R. Giger, who is best known for designing the Xenomorph creatures for Ridley Scott's award winning film Alien and its sequels. Many Xenome creatures in the game also resemble Giger's work. Parts of the Gunman Chronicles world seem to contain influences from novels such as Dune.