Doom was released with three episodes for the PC in 1993 and was given a fourth episode in 1995 and re-released as The Ultimate Doom. Recently, in 2019 - 25 years later - one of Doom's original creators and chief level designers, John Romero, created a fifth episode for the game called Sigil. This "DLC" or expansion is free to download and plays best on the GZDoom engine together with the Project Brutality mod.
The Ultimate Doom, Brutal Doom, Project Brutality 3.0, Episode 5: Sigil, Baphomet's Demesne, E5M1
Music: Money in the Grave (Instrumental) by Drake