This will most likely be your first level doing all 3 as they are easy challenges, so you will probably unlock: Each leg, each arm, in front or behind them will each perform a different glory kill. Variety is the Spice of Death: Perform 5 different glory kills on The Possessed: If you have the explosive shot then fire at the ground near 2 Possessed enemies. If you have the burst charge then you should charge it up and line up multiple Possessed enemies and hope to get 2. You should use a weapon mod on the shotgun for this. Two-fer: Kill 2 of The Possessed with one trigger pull from the Shotgun:
You can track your progress on the map screen. You do not have to finish all 3 in a single run, so if you miss any then you can use mission select to finish them. This is the first level containing challenges. 2 guides Resource Operations (Level 2) Challenges