Killing orcs for hours.

I found myself replaying some Challenge mode over and over again killing orcs.

Shooting them in the head, exploding their heads, cutting off their heads, throwing them off cliffs, burning them with exploding barrels, backstabbing, causing monsters to attack them, mind controlling them to kill other orcs and then have their heads explode when I was done with them, etc, etc.

At times you have to fight 30+ orcs AND kill the Captain/warchief3

Killing orcs is fun, VERY fun.

So yea, as you can tell the best part of the game is killing orcs.