6 Against the Dark
6 Against the Dark and 6 Days to Adventure are flavors of essentially the same game; one is horror of the haunted house variety and the other evokes big globe-trotting, treasure hunting adventure potboilers (or pulp adventure, if you prefer)
Built around a board-game-style three Act structure with a simple dice resolution mechanic (using a “purchase results” method). Like 6 Hours, designed for one shot, or at least self-contained stories; you start at the beginning, rough out a character in broad strokes, then play through the steps (scenes) in order.
Designed for solo but with more room (and less constrained roles) than 6 Hours to Midnight for multiple players. The framework is also suitable for running by a GM.