ME3: Defeat a harvester.

ME3: Destroy an Atlas dropped from orbit.

ME3: Obtain two non-customizable suits of armor.

ME3: Kill 10 guardians with headshots from the front while their shields are raised.

Kill 100 enemies with melee attacks in Mass Effect 1, 2 or 3

ME3: Escape a Reaper in the galaxy map.

ME3: Modify a weapon.

ME3: Chase down an assassin.

ME3: Lift 100 enemies off the ground with powers.

ME2: Incinerate the armor of 25 enemies

ME2: Fully upgrade a weapon

ME2: Visit 100% of the planets in an unexplored cluster

ME2: Hit 20 different targets with multiple biotic powers to combine the effects