U originalu igra je igra trebala koristiti GURPS (Generic Universal Role Playing System) sustav, ali se zbog nesuglasice Interplaya i GURPSovog autora Steve Jacksona težište prebacilo na Interplayev SPECIAL sustav (izvedenica sedam temeljnih Fallout statova S trength, P erception, E ndurance, C harisma, I ntelligence, A gility i L uck).