Most games just change a few values when difficulty goes up. HP of enemies, damage of their guns(more), damage of your guns(less), and other things of that nature. I've always thought quick-saving, or being able to save anywhere, has toned down difficulty. I hate checkpoints, but they do add a type of difficulty. Like FarCry on whatever the hardest difficulty was called. You'll never be satisfied by anything. Ever. People won't play a game that only 1% of people who play it can beat. That's not fun, that's more of a job that you pay for. You have my pity.