Gamma World has seen many incarnations, starting off in 1978 as a TSR stand-alone game, then being rewritten for their Alternity system and now available as a D20 game. The basic premise has not changed, it is still a weird world in which mutants and strange creatures are the norm. Original versions had atomic radiation as the cause of the changes, while in the latest version biotechnology and nanotechnology underly the oddness you expect to find.
While the D20 version is based on the D20 Modern ruleset, there are also notes for those who would prefer to use Dungeons & Dragons 3.5.
Setting Page last updated: 5 July 2005