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.
Reach level 20 in multiplayer or level 60 in single-player.
Hijack an Atlas mech.
Upgrade any weapon to level 10.
Promote a multiplayer character to the Galaxy at War or import an ME3 character.
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.
Finish all multiplayer maps on Gold or all single-player missions on Insanity.
Make the final assault.
Defeat an old adversary.
Deliver most of the Galaxy at War assets to the final conflict.
Send a warning across the galaxy.
Extract ancient technology.
Call down an orbital strike.
Disable a group of fighter squadrons.
Sabotage a dreadnought.
Discover an enemy's monstrous origin.
Establish or rekindle a romantic relationship.
Evacuate a scientific facility.
Win a political stand-off.
Explore a lost city.
Survive the swarm.
Kill 100 enemies with melee attacks.
Defeat a harvester.
Overload the shields of 100 enemies.
Destroy an Atlas dropped from orbit.
Perform any combination of 50 biotic combos or tech bursts.
Stop a Cerberus kidnapping.
Obtain two non-customizable suits of armor.
Dispatch 10 probes to retrieve people or resources in Reaper territory.
Kill 10 guardians with headshots from the front while their shields are raised.
Bring a veteran officer aboard.
Kill 1,000 enemies.
Attain the highest level of readiness in each theater of war.
Escape a Reaper in the galaxy map.
Visit a store in the single-player campaign.
Chase down an assassin.
Set 100 enemies on fire with powers.
Return to active duty.
Evolve any of your powers to rank 6.
Reach level 15 in multiplayer or level 50 in single-player.
Lift 100 enemies off the ground with powers.
Kill 250 enemies.
Finish all multiplayer maps or all N7 missions in single-player.
Complete three multiplayer matches or five N7 missions.
Kill a brute while it's charging you.
Complete one multiplayer match or two N7 missions.
Modify a weapon.
Start a character in multiplayer or customize a character in single-player.
Learn more about the Prothean Empire.
Find all required intel to help Eden Prime's colonists.
Uncover an ancient secret.
Rescue a civilian from Reaper forces.
Investigate a sinister conspiracy.
Use clues to pinpoint the exact location of an objective.
Free Omega from Cerberus Occupation.
Complete all the Command Center side-missions on Omega.
Find the Talon leader.
Defeat a group of Spectre-level opponents on Normal, Hardcore, or Insanity.
Score 9999 points in the combat simulator on Normal, Hardcore, or Insanity.
Investigate a strange occurrence in the combat simulator.
Win a prize at one of the arcade games.
Throw a party for your friends.
Stop an out-of-control scheme before it's too late.
Infiltrate an enemy stronghold with your crew.
Go undercover to follow a lead.
Discover a plot against you.