I remember reading a power based/super hero like game where each character was allowed to list a few powers. Each power was defined by examples of what it was or wasn't possible to do with that power. Examples are given for what's possible at each of a number of difficulty levels; the mundane things that can be done without effort, difficult things that can be done but not necessarily reliably, taxing things that may be possible but stretch the limits of the power, and impossible things that the power can't accomplish (These aren't the exact difficulties used in the game). For example, a character's powers might be described as follows
Hurk, stone avenger
- Summon Stone Hurk can summon large stones from the earth or create smaller stones in his hands. Larger or more intricate shapes are more taxing. mundane: create first sized rocks, raise or sink the ground up to the size of a cart, difficult: form stone into specific shapes, raise or sink the ground the size of a building, taxing: raise a castle, encase someone in a stone prison or fortification, raise a stone wall in reaction to an attack impossible: raise a mountain, create valuable minerals, create stone that isn't touching either Hurk or the ground
- Living Earthquake When Hurk is angry, he breaks things relentlessly in pursuit of the target of his wrath. Even he cannot control his wrath. mundane: become angry with something. while angry destroy an undefended object, while angry resist attempts to mentally control him, difficult: while angry destroy an opponents armor or equipment, while angry resist attempts to physically control him, taxing: end his anger, while angry destroy a cart or vehicle, impossible: while angry, do anything other than relentlessly pursue and destroy everything between him and the target of his wrath
A character would have a small handful of such powers. In my imagining of the game, part of the purpose of the powers is for the characters to help define what is and isn't fictionally possible in the world, and how impossible it is for everyone else. If creating a stone structure is difficult for Hurk, stone avenger it is likely taxing, time-consuming, or impossible for everyone else.
As characters leveled up, they could either add new abilities to their powers or make existing abilities easier to use, for example moving something that was taxing before to be merely difficult.
What game is this?