Full list of all 68 Mass Effect 3 achievements worth 1,550 gamerscore. It takes around 50-60 hours to unlock all of the achievements in the base game.
The base game contains 50 achievements worth 1,000 Gamerscore, and there are 4 DLC packs containing 18 achievements worth 550 Gamerscore.
Kill 5,000 enemies.
Deliver most of the Galaxy at War assets to the final conflict.
Attain the highest level of readiness in each theater of war.
Overload the shields of 100 enemies.
Kill 10 guardians with headshots from the front while their shields are raised.
Hijack an Atlas mech.
Reach level 20 in multiplayer or level 60 in single-player.
Make the final assault.
Mission accomplished.
Complete Mass Effect 3 twice, or once with a Mass Effect 2 import.
Finish the game on Insanity without changing difficulty after leaving Earth.
Kill 100 enemies with melee attacks.
Promote a multiplayer character to the Galaxy at War or import an ME3 character.
Finish all multiplayer maps on Gold or all single-player missions on Insanity.
Upgrade any weapon to level 10.
Extract ancient technology.
Send a warning across the galaxy.
Establish or rekindle a romantic relationship.
Finish all multiplayer maps or all N7 missions in single-player.
Defeat an old adversary.
Call down an orbital strike.
Disable a group of fighter squadrons.
Kill 1,000 enemies.
Reach level 15 in multiplayer or level 50 in single-player.
Complete three multiplayer matches or five N7 missions.
Sabotage a dreadnought.
Evacuate a scientific facility.
Discover an enemy's monstrous origin.
Win a political stand-off.
Explore a lost city.
Perform any combination of 50 biotic combos or tech bursts.
Defeat a harvester.
Survive the swarm.
Lift 100 enemies off the ground with powers.
Obtain two non-customizable suits of armor.
Complete one multiplayer match or two N7 missions.
Dispatch 10 probes to retrieve people or resources in Reaper territory.
Destroy an Atlas dropped from orbit.
Visit a store in the single-player campaign.
Bring a veteran officer aboard.
Modify a weapon.
Stop a Cerberus kidnapping.
Kill 250 enemies.
Evolve any of your powers to rank 6.
Escape a Reaper in the galaxy map.
Kill a brute while it's charging you.
Set 100 enemies on fire with powers.
Chase down an assassin.
Return to active duty.
Start a character in multiplayer or customize a character in single-player.
Find all required intel to help Eden Prime's colonists.
Learn more about the Prothean Empire.
Investigate a sinister conspiracy.
Uncover an ancient secret.
Use clues to pinpoint the exact location of an objective.
Rescue a civilian from Reaper forces.
Find the Talon leader.
Free Omega from Cerberus Occupation.
Complete all the Command Center side-missions on Omega.
Discover a plot against you.
Go undercover to follow a lead.
Infiltrate an enemy stronghold with your crew.
Stop an out-of-control scheme before it's too late.
Throw a party for your friends.
Win a prize at one of the arcade games.
Investigate a strange occurrence in the combat simulator.
Score 9999 points in the combat simulator on Normal, Hardcore, or Insanity.
Defeat a group of Spectre-level opponents on Normal, Hardcore, or Insanity.