Pratchett was an avid video game player, and collaborated in the creation of a number of game adaptations of his books. He favoured games that are "intelligent and have some depth", citing "Half-Life 2" (2004) and fan missions from "Thief" as examples. The red army in "Interesting Times" alludes to the game "Lemmings", and when asked about this connection, Pratchett stated, "Merely because the red army can fight, dig, march and climb and is controlled by little icons? Can't imagine how anyone thought that ... Not only did I wipe "Lemmings" from my hard disk, I overwrote it so I couldn't get it back." He described ' (2006) as "wonderful", and used many of its non-combat-oriented fan-made mods. Pratchett wrote dialogue for an "Oblivion" mod which added a Nord companion named Vilja. He also worked on a similar mod for ' (2011) which featured Vilja's great-great-granddaughter.