Emergence in Games
Emergence is a well-known concept in game design. Emergent gameplay comes when players interact with the mechanics of the game creating situations that have not been deliberately designed.
This could be part of the game design or it could be unintentional. For instance, the game may offer several tools to solve a puzzle, but allow the player to use them in any way they see fit. If the puzzle requires you to reach an item that is high up, there could be an infinite number of ways to get it. Use a grapple hook, build a tower, make a jetpack and so on.