The problem is when you include an easy mode, you normally don't have some types of challenges in the game.  Take God of War, when you go for "hard mode" all that changes is the hit point pools.  It's challenging only in the most limited concept of challenging and in the easy mode you kill gobs of enemies and quickly go though the world, in hard mode you stand around slowly attacking the same AI doing the same things for longer.  What most gamers like is close to one hit kills with challenging foes and environment not to feel like you are attacking a brick wall with a ice pick.<p>Now if you add enemies to hard mode, require some sort of finishing move, or add extra ambushes that's different.  But when you build a game for easy mode, and tack on pointless challenges it just feels cheap.<p>PS: One option would be to have extended death, where you "kill" enemies but they keep attacking for a few seconds but if you walk away they quickly die.  It makes the world feel more real and adds more challenge without slowing down the pace of the action.