As Thomek has said, if you're starting to find the game too easy there's many ways to gimp yourself.
Take off the armour. Use a short/unbalanced weapon. Play an archer with 50 one hand wpf. If anything, you'll get a greater sense of accomplishment if you do manage to kill something.
If you're not willing to do that, then you're probably not measuring skill in terms of actual skill, but in kills.