Wolfenstein is a fictional world created by Silas Warner in 1981, based on Germany during World War II. Initially, the titles set in the universe were strictly military themed, but, in 1992, id Software began adding elements of science fiction and religious fiction to the world. The series now features a dozen games, a comic book series, many fan projects, and even an attempt to make a film, but it never materialized.
The game series began as a stealth game where you would have to try and avoid guards and sneak through Nazi barracks, but id Software changed it into an action first-person shooter. Later titles continued with the strong action elements, but also began reintroducing stealth elements in certain missions.
I didn't learn about the Wolfenstein franchise until over a decade after the first game had been released. The first game I saw in the series was Wolfenstein 3-D, and I assumed id Software created the game from scratch. I was at a friend's house who had acquired the shareware version of the game and I only saw a little bit, but I was really impressed, especially with the explicit cartoon gore and the screams the Nazis shouted out when you killed them! Later, my brother got a shareware release of Wolfenstein 3-D which had been modified using a map editor. I loved playing with the map editor and figuring out how it worked, and made my own weird levels. At some point, I got to finally sit down and play the an intact shareware copy by myself and really enjoyed the game. In the mid 1990s, a friend of mine lent me his pirated disks for the full game. After playing it for awhile, I quit the game and read the exit text where the developers threatened to erase my hard drive! I panicked and quickly deleted the game, however, after thinking about it for awhile, I doubted they would actually do that, and reinstalled it. Because I had been taught the MLI cheat code, I never tried to play the game seriously, and just cheated my way through every mission. Later, I learned about the -goobers code, which helped me understand more about the internal game engine. I made a lot of new maps for the game, but never bothered to save any of them. Around this time I also played a little bit of Spear of Destiny, but also never made an effort to try beat it.
I remember seeing Return to Castle Wolfenstein on shelves at the mall, but never bought it or played it. Sometime around the late 2000s, I tried to actually play Wolfenstein 3-D properly and beat the first thee episodes on "Bring 'em on" difficulty. In 2018, I bought a Humble Bundle of Wolfenstein 3-D, Spear of Destiny, and Return to Castle Wolfenstein, finally becoming a legal owner, and played through Return and beat it. I wasn't that impressed with Return so I haven't sought out any of the more recent titles.
Although I understand how important Wolfenstein has been to the gaming industry, I've never really cared much for the series because I've never really found any of the games to be really fun. They have wonderful shock value, and the 3D engine was a marvel at the time, but that isn't what makes a game enjoyable.
Titles in the Wolfenstein series seem to be released in spurts. Castle Wolfenstein and Beyond Castle Wolfenstein were released in the early 1980s, by Muse, then there was a dry spell. id Software successfully convinced Warner to let them expand the series and they created Wolfenstein 3-D in 1992, then made various expansion packs, and ported the tiles to many different platforms throughout the 1990s, but no unique titles were released until 2001 with Return to Castle Wolfenstein. There was another long gap until it was followed up with Wolfenstein, then another five years until the next game. However, in the past five years, the series has been seeing a new game once a year.