The Complete 3D-ACTION Accessory Pack addon - Descent

To run the Shareware you need Windows XP Compat on Windows 7 or 10, Windows XP users are fine running it,

Running Levels in Doom or Doom II requires the Doom Collectors Edition launcher or a sourceport such as GZDoom, Heretic levels require a sourceport.

Running levels in Rise Of The Triad requires a sourceport such as WinROTT, To add the level in and launch it, Running levels in Dark Forces requires placing the files of the "levels" folder into the Dark Forces Level folder, Descent is the same way, But requires editing of the Ini TXT file.