Andi's article, The Cult of Doom, can be found in the June 2015 UK or July 2015 US issue of PC Gamer magazine. It's the one with Star Wars: Battlefront on the cover. Three screenshots of The Adventures of Square got in, as well as a whole bunch of words about Doom from me, Jimmy, and even newbie-mapper/oldie creator Cyriak, maker of megawad Going Down.
Get a copy and read it! You can probably find it in major bookstores and magazine outlets.