The 2-player version of this game is Gottlieb's 1977 'Fire Queen'. Gottlieb Domestic & Export Sales Sheets for Vulcan: 3575 total Domestic Sales: 1119 Export Sales: 2456, of which 576 were sold to Germany. The above total does not include 285 Sample games produced in 1977 per handwritten documentation identified by Wayne Neyens as coming from Bob Malvasio, a draftsman for Gottlieb whose initials RHM can be found on schematics.