What is the Threshold Engine?

The Threshold Engine is a tabletop roleplaying game system centered on a bounded single-d20 “Roll-Under High” (or blackjack-style) resolution window. In this framework, players succeed by rolling under or equal to their skill rating while remaining above an environmental or self-imposed Stunt Threshold. Rather than using high numerical scaling or floating modifiers, the system drives narrative tension, grit, and tactical resource management, making it particularly suited for grounded, high-stakes genres.