Gaming

It's pretty hard to make levels of difficulty that actually change things enough outside of either giving the enemies more damage and HP or simply adding more enemies, or in scored games having higher score thresholds for higher ranks (these can be anything from an actual score to the speed you finished and everything in between that's basically just a number that you can compare to another number).

It certainly can be done, though. I can't help but think about the bots in counter-strike. They range from braindead drooling moving targets to Terminator machines that can 1 tap you with a pistol from across the map. They actually have a difficulty scale that's more than simply being tougher to kill and hurting you more. It affects how they move around, the speed they begin shooting, their accuracy, etc. I don't know why these kind of bots do not extend to pretty much any game with enemies. Just give them 3 sets of behavior that makes them easier or harder to deal with.