 The series had sold over 18 million copies as of 2017, with Livingstone's "Deathtrap Dungeon" selling over 350,000 copies in its first year alone.Livingstone wrote another twelve "Fighting Fantasy" gamebooks, including "The Forest of Doom", "City of Thieves" and "Caverns of the Snow Witch" before marking the 30th anniversary of "The Warlock of Firetop Mountain" with a new gamebook, "Blood of the Zombies", in 2012, and with "The Port of Peril" in 2017 for the 35th anniversary.In the mid-1980s Livingstone did design work for video game publisher Domark; he returned to the company in 1993 as a major investor and board member.