First check out The Wolfenstein 3D Dome, The Diehard Wolfers' Forum, and The Wolf3D Haven Forums.

Wolfenstein 3D demos, abandoned/incomplete mods, authors' web pages, cheats, commentary, Easter eggs, forums, guides, mirror downloads, news, previews, programming code changes, reviews, saved games, screenshots, and videos:

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Registered Wolfenstein 3D

Shareware Wolfenstein 3D

Registered Spear of Destiny

-Gloom By Acord Games...
      ...19 Levels. Includes Rise of The Triad characters. It's a little bit different graphics engine that uses Castle Grom By Raziel as a base.

Shareware Spear of Destiny