One of the more pleasant surprises in recent memory was when Bethesda and id Software released revamped versions of DOOM ($4.99) and DOOM II ($4.99) last year to celebrate the franchise’s (roughly) 25th anniversary. Over the course of the last year and a half the developers have been releasing frequent additional updates that have featured modern touches like proper widescreen support, higher frame rate support, physical controller support, and plenty of other welcome additions. Probably the biggest new feature was support for add-ons, which is just another way of saying that Bethesda built in support for a curated selection of mod packs and expansions that have been released by the DOOM community over the past couple of decades. The frequency of new add-ons being released has really been impressive since add-on support was added this past January, and today that catalog of free extra content grows even more with the release of the DOOM Zero expansion which first arrived on PC last year. Check out its trailer.

Perhaps the most impressive part about DOOM Zero is that it’s the product of just a single person, a modder named Christopher Golden who is based in South Africa. Bethesda has posted an interview with Golden on the Doomslayer blog that goes into more detail about his history and the inspirations behind this expansion. DOOM Zero was Golden’s vision to create a game with maze-like branching pathways and puzzle solving but with the extraordinary combat of DOOM. This means you might need to put your thinking cap on a bit more than usual while conquering its 30+ new levels. If you own either of the revamped versions of DOOM or DOOM II on iOS, or any of the other platforms it’s available on for that matter, you can download DOOM Zero from the in-game add-ons menu for free right now.