10 One-Of-A-Kind Video Game Mechanics
8. The Nemesis System - Middle-Earth: Shadow Of Mordor & Shadow Of War
When it comes to generating unique player experiences, it's hard to think of anything better than the Nemesis System used in the Middle-Earth: Shadow of Mordor and its sequel, Shadow of War.
The phenomenal Nemesis System uses artificial intelligence to allow NPCs to remember your interactions and alter their behaviour accordingly. The way you treat an enemy can have unforeseen implications you'd never see coming, leading to a litany of experiences only you will have.
This tool for individual story generation resulted in resounding critical acclaim. Unfortunately, it is an outlier on this list, as this mechanic being one-of-a-kind isn't really a good thing.
Many players called out other developers for not taking advantage of this groundbreaking system after Shadow of Mordor's release. However, it is not their fault, as Warner Bros. has a patent on the system that won't expire until 2035 (confirmed here by IGN). Any devs who used it would be infringing on copyright laws, which is why no one has dared.
It is fair to want exclusivity over a system you built, but it just stinks of wasted potential.