Wolfenstein
Silas Warner, an American programmer and an employee of software company Muse Software, was a pioneer of early video game development, especially the stealth genre. He had access to computers in college, and when he worked for the IBM Mainframe architectures before joining Muse Software. The computer he used for game-development, P.L.A.T.O., was one of the firsts with multiple functioning terminals and an example of early computer networks. Warner developed, with P.L.A.T.O., a series of classic video games like his flight simulator and arcade shooter. Inspired by the arcade shooter video game "Berzerk" and the 1961 war film "Guns of Navarone", he developed "Castle Wolfenstein", a stealth-adventure video game in which the player controls an unnamed American prisoner of war as he steals German files containing secret war plans, while avoiding, disarming or at times killing hostile guards and trying to escape the fortified Nazi stronghold 'Castle Wolfenstein', set in World War II. The game was published in 1981 by Warner's company M.U.S.E. Inc. (Muse Software).
Wolfenstein 3D
"Wolfenstein 3D" was a critical and commercial success, garnering numerous awards and selling over 200,000 copies by the end of 1993. It is widely regarded as having helped popularize the first-person shooter genre and establishing the standard of fast-paced action and technical prowess for many subsequent games in the genre, as well as showcasing the viability of the shareware publishing model at the time. FormGen developed an additional two episodes for the game, while Apogee released a pack of over 800 fan-created levels. Id Software never returned to the series, but did license the engine to numerous other titles before releasing the source code for free in 1995, and multiple other games in the "Wolfenstein" series have been developed by other companies since 2001.