Wolfenstein
The "Wolfenstein" series of video games started with the 1981 stealth-adventure video game "Castle Wolfenstein". It was developed by American programmer Silas Warner, a pioneer in the early eras of video gaming, especially the stealth genre. It was published by his (then) company M.U.S.E. Inc. (Muse Software). The player controls an unnamed American prisoner of war as he steals war files containing information about secret German war plans while avoiding or sometimes killing guards, and tries to escape the fortified Nazi stronghold Castle Wolfenstein, set during World War II. The game is often credited as one of the first video games of the stealth genre, since it focuses more on avoiding or disarming enemies, and killing them is considered a last resort.
Splash Damage
Following Market Garden's success, Activision and id Software asked Splash Damage to produce three additional multiplayer maps for the "Return to Castle Wolfenstein Game of the Year Edition". The same year, Splash Damage partnered with the two companies to develop "", a stand-alone expansion based on "Return to Castle Wolfenstein". The Windows version of "Wolfenstein: Enemy Territory" was released online for free on 29 May 2003, with Linux and Mac versions following later. "Wolfenstein: Enemy Territory" won several Game of the Year and Editor's Choice awards and remains one of the most popular online first-person shooter titles.