So I recently beat Shadows of Mordor and found it got way too easy after you started getting more skills unlocked. So this the challenge: You must beat beat the game with no points in the skill tree except one point in the skill death threat. You will use death threat towards each war chief as soon as you get it. You can spend currency to unlock rune slots but nothing more.
I think this should make things a little more interesting for the moment, I'll test it soon and tweak it as I see fit. Happy hunting!