Players interacting with game systems in a way not accounted for in the initial design. Often this involves using unexpected strategies (such as the combination of physics systems and explosions which led to the “rocket jump”) or forcing interaction between usually separate mechanics. Emergent behavior–systems interacting with one another unexpectedly–is also possible, particularly in complex games with many overlapping mechanics.

“Environmental systems in Black & White rely on physics and a set of real-world properties, from which came the emergent mechanic of superheating boulders with makeshift wooden stoves.”