Doom — the original 1993 game —has an unofficial sequel courtesy of its creator. Called Sigil, it’s a huge mod that Romero worked on over a two-year stretch and is now offering free to everyone.

Sigil was also packaged up with a bunch of other premium goodies but they’re all sold out. The important part, the entire playable experience, is fully gratis. It’s a fifth chapter, coming after Doom’s fourth episode (“Thy Flesh Consumed”) and before 1994’s Doom 2. At the end of Doom, Doomguy is going back to Earth to save it from Hellspawn in Doom 2. But in Sigil, Baphomet has “glitched the final teleporter” that takes him “to even darker shores of Hell.

“You fight through this stygian pocket of evil to confront the ultimate harbingers of Satan,” Romero said. Sigil comprises nine levels used in both single-player and cooperative mode, and is a “megawad,” which is basically a super large batch of .WAD files that’s about the size of a full game. Romero used Pascal van der Heiden’s Doom Builder 2 to make the levels.

Romero said he worked on it during time off and weekends over 2017 and 2018, and intended it for Doom’s 25th anniversary last year. Delays to the production of the physical edition and its goodies pushed the release back to now.

Of note, for the devilishly low price of €6.66 players can get a soundtrack from master shredder Buckethead (playable only in the megawad; not MP3s). The other two editions were stocked with a lot more goodies but they were sold out soon after pre-orders were taken in December. Too bad, as Romero called the Beast Box version “the most evil game box I’ve ever seen.”