Use the A.R.E.S. to kill the Brutalisk in the “Piercing the Shroud” mission on Normal difficulty.
Dodge a Raven Seeker Missile in a Melee game.
Score the rank of Gold in all the challenge missions.
Complete the “Left 2 Die” scenario on Hard difficulty.
Don’t take damage from the Archangel in the “Back in the Saddle” mission on Normal difficulty.