Tom Mustaine is a game designer who has co-founded Ritual Entertainment and, after Ritual was bought by MumboJumbo, co-founded Escalation Studios. Escalation Studios was purchased by ZeniMax Media, parent company of Bethesda Softworks, in 2017. Escalation was made a part of Bethesda, becoming Bethesda Game Studios Dallas, at which Mustaine is currently an executive.
His Doom-related work includes one of the Master Levels for Doom II, Paradox; the commercial add-on Perdition's Gate published by WizardWorks, and two DWANGO WADs: 4dwango.wad for Heretic, and 1dwango.wad for Doom II, a compilation of levels including five maps of his own and two music tracks he wrote. He also contributed some of the music tracks used in TNT: Evilution.
More recently, he worked on Doom Resurrection.