PowerFrame Core Rulebook

From the introduction: PowerFrame is a universal toolbox roleplaying game. It provides a solid, powerful framework of rules that allow you to build and play in your own action-adventure settings. ... PowerFrame excels at games in which civilisation is tenuous, travel is treacherous, and creatures are dangerous – fantasy worlds, frontier societies, the postapocalypse. Characters often have humble beginnings, but can develop into epic action heroes.