“Doom” designer John Romero and his studio, Romero Games, is releasing a free “megawad” called “Sigil” for the original 1993 first-person shooter.

In “Doom” parlance, a megawad is a fan-made batch of 15 levels or more. “Sigil” has 18 levels — nine single-player and nine deathmatch. It’s the spiritual successor to the fourth episode of “Doom” and it picks up where the original left off, according to its official website.

In addition to the megawad, Romero Games is also offering two limited edition “Sigil” fan boxes created by Limited Run Games. They feature music by legendary metal guitarist Buckethead, including a custom song written for “Sigil,” along with cover art by metal album artist Christopher Lovell.

Romero Games

The “Sigil” Beast Box is inspired by the Id Anthology box and contains:

A 16GB 3-1/2-inch floppy disk-themed USB with the free megawad data and extras

A 2-disc booklet styles case with the megawad data and full Buckethead soundtrack, as well as behind-the-scenes info on the original game and the megawad’s development

An 8″ x 10″ art print signed by Christopher Lovell

A “Sigil”-themed coin

A pewter statue of John Romero’s head on a spike

An XL-sized “Sigil” t-shirt

One “Sigil” sticker and one Romero Games sticker

The “Sigil” Standard Edition box contains:

A standard-sized “big box” featuring artwork by Christopher Lovell

A 16GB 3 1/2-inch floppy disk themed USB that includes the free megawad data and extras

The Buckethead sountrack

The two stickers

“Sigil” pre-orders will only be open from Dec. 10 through Dec. 24. Both the free megawad and the boxes are expected to ship in mid-February. Players need a copy of the original 1993 registered version of “Doom” in order to play the new levels.