SIGIL™ is a free megawad for the original 1993 DOOM® created by John Romero. It contains nine single-player and nine deathmatch levels. The free megawad will be released in April 2019 and requires players own the original 1993 registered version of DOOM® in order to play. SIGIL™ is the spiritual successor to the fourth episode of DOOM®, and picks up where the original left off.
Download the latest version of SIGIL (v1.21) here - Moddb.com
You can play SIGIL with several modern source ports such as GZDOOM, or the Steam version of DOOM. You must own the original registered DOOM or The Ultimate DOOM to play. SIGIL is playable in Co-operative, Deathmatch, and Single-Player modes. SIGIL is for PC/Mac. Limited Run Games has created fan boxes for physical distribution that will reach customers in April 2019. After the boxes have been shipped, the free SIGIL megawad will be available for download at SI6IL.com. UPDATE April 7, 2019: Due to a delay in physical production of some of SIGIL's pieces, fan boxes will ship in the first week of May. The free megawad will be made available one week after fan boxes begin shipping so paying customers can play SIGIL first.