While he became infamous later for Daikatana, a hugely ambitious and hyped up project that ended up failing massively upon release, John Romero is best known as the genius who, working with John Carmack at id Software, created some of the most pioneering games of the industry. Wolfenstein, DOOM, and Quake were all among his creations.

Now, with DOOM 25 years old, Romero seems to be celebrating the original game with something new. You may remember that he was teasing an announcement recently—that announcement has led up to SIGIL, a free “megawad” mod for the original DOOM, containing nine single player and nine deathmatch levels. You do need to own a registered copy of the original game to be able to run this, but that shouldn’t be too difficult, given how freely DOOM has been distributed in the years following its release (legally, I mean).

SIGIL will release in February, and, as stated above, will be absolutely free. However, Limited Run Games will also launch a physical copy of the game, with music by metal guitarist Buckethead. So if you like having physical copies of your games, that’s something you will want to keep an eye out for.