Single Player: Kill 4 enemies in a row with headshots

Complete In at the Deep End

Completed a round of Gun Master

Received all 4 support efficiency ribbons

Disarmed the bomb in under 20 seconds in The Eleventh Hour

Got one kill with the Gunship

Use the upgraded Deadeye secondary fire to kill 2+ enemies, 5 times

Use the Deadeye to kill 20 snipers

Freeze 5 enemies at once and destroy them with a blast of the Cryogun's secondary fire

Use the EMP to take down 10 Steelhead Auger shields

Destroy 10 Warden vehicles while on the train

Complete Campaign Mode on any difficulty

Detonate multiple Magnum rounds to kill 2+ enemies at once, 5 times