If you've played the game before it's going to be easier because you know what's coming and where to go.
I started out on survivor and died often trying to get all the guys killed in the most efficient manor. I didn't think it was hard, just not easy. I liked to explore and then start over using the best path and finding survivors.
I was one bullet shy of unlocking the cannibal captives otherwise I would've snagged all 20.
-Insert something creative here-
( that doesn't include stats that no one really cares about or some poorly photoshop'd image with your name stuck in it. )