Originally Posted by RampantCoyote
Simple positive feedback example - a side-scrolling shooter. You get levels which are insanely hard UNLESS you are good enough to get the power-ups… in which case, it's actually easy. Your power-ups have you shooting a zillion bullets per second, wiping out whole waves of enemies in moments - they hardly even have time to shoot.
So if you are fairly skilled, the game gets easier.
But woe betide the player who isn't good enough to get the pick-ups. The level is going to be much, much harder for the unskilled player. So the difficulty is always about the same regardless of your progress in the game.