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.
Rise of the Triad
"Rise of the Triad" began its life as a follow-up to "Wolfenstein 3D" (though it reportedly shares some similarities with Hall's "Doom Bible", which laid out Hall's conception of the video game "Doom" and even shares the name of one of the protagonists). The working titles of the game were "Wolfenstein II" and "Wolfenstein 3D: Rise of the Triad". It was to use the same game engine code as "Wolfenstein 3D", and have new levels, art, and characters. The artwork took around six months to do. As the game was getting into deeper development, project leader Scott Miller was contacted by John Romero, informing Miller that the project had been cancelled. Miller suspected that this was because id Software did not want to draw the spotlight away from their upcoming game, "Doom". In order to keep as many of the numerous game assets the team had already created from going to waste, Tom Hall came up with a new storyline which still incorporated the Nazi themes seen in the Wolfenstein series.