The first time we heard anything about John Romero's fifth, and unofficial, episode for 1993's Doom was last December. The mod promised nine new single-player levels and nine deathmatch levels of fun for free. However, there were also a pair of paid editions that brought extra goodies with the game. In February, Romero announced that the game was being delayed and would ship in April; that didn't happen either.
Now, the game has finally landed; Sigil is finally available to download at no cost via Romero's website. Gamers who fancy the soundtrack by Buckethead can download a version of the game that includes the music for a devilish $6.66.
The caveat to this game is that it requires the original Doom circa 1993 to play. If you want to partake the free Sigil expansion, you will need to buy the original game, not the later remake. You can get the 1993 Doom on Steam, the Humbel Store, and GOG.
The reason for the delays is that there was some sort of issue with the package for the special editions of the game. Romero simply didn't want people getting the free version before paying customers received their game. You can download the Sigil megawad here.
If you want to know what Sigil is about, Romero explains it best. He wrote, "After killing the Spiderdemon at the end of E4M8 (Unto the Cruel), your next stop is Earth — you must save it from hellspawn that is causing unimaginable carnage. But Baphomet glitched the final teleporter with his hidden Sigil whose eldritch power brings you to even darker shores of Hell. You fight through this stygian pocket of evil to confront the ultimate harbingers of Satan, then finally return to become Earth's savior. In summary, rip and tear!"