Brute Force Achievement
Finish the objectives using only the Brute Shot, melee and grenades in Operation D, Mission 1
This mission will introduce Brutes and the Brute Shot. At the start of the level you'll have a Brute Shot right next to you, and for the duration of the very short mission, use the Brute Shots and grenades on the two doors you need to blow up, and melee the Brutes that appear for more Brute Shot ammo. Be sure to run around to pick up grenades from enemies your teammates kill, and from the couple of grenade boxes, to make the mission go quicker.