1st ed by Bob Charrette, Paul Hume (1981) FGU
A generic post-nuclear-apocalypse RPG, supporting various sub-genres (mutants, survivalist, etc.). The system is a complex skill-based, where action is resolved by rolling a d20 under (skill/5) or (attribute/2). Character creation uses limited point allocation, with some random rolls. Notably, besides standard attributes it has "aptitudes" in skill categories: charismatic, combative, communicative, esthetic, mechanical, natural, and scientific. Combat is quite complex, with a two-page flowchart explaining the combat sequence(!!). It uses basic to-hit, hit-location, and damage rolls with armor subtracted -- but with many special-case criticals.