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.
Bring a veteran officer aboard.
Evolve any of your powers to rank 6.
Kill 250 enemies.
Upgrade any weapon to level 10.
Promote a multiplayer character to the Galaxy at War or import an ME3 character.
Reach level 20 in multiplayer or level 60 in single-player.
Mission accomplished.
Complete Mass Effect 3 twice, or once with a Mass Effect 2 import.
Make the final assault.
Defeat an old adversary.
Hijack an Atlas mech.
Deliver most of the Galaxy at War assets to the final conflict.
Attain the highest level of readiness in each theater of war.
Kill 100 enemies with melee attacks.
Lift 100 enemies off the ground with powers.
Kill 10 guardians with headshots from the front while their shields are raised.
Send a warning across the galaxy.
Kill a brute while it's charging you.
Finish all multiplayer maps or all N7 missions in single-player.
Extract ancient technology.
Reach level 15 in multiplayer or level 50 in single-player.
Call down an orbital strike.
Kill 1,000 enemies.
Establish or rekindle a romantic relationship.
Disable a group of fighter squadrons.
Complete three multiplayer matches or five N7 missions.
Evacuate a scientific facility.
Sabotage a dreadnought.
Discover an enemy's monstrous origin.
Win a political stand-off.
Perform any combination of 50 biotic combos or tech bursts.
Explore a lost city.
Defeat a harvester.
Complete one multiplayer match or two N7 missions.
Survive the swarm.
Destroy an Atlas dropped from orbit.
Dispatch 10 probes to retrieve people or resources in Reaper territory.
Stop a Cerberus kidnapping.
Escape a Reaper in the galaxy map.
Set 100 enemies on fire with powers.
Obtain two non-customizable suits of armor.
Visit a store in the single-player campaign.
Chase down an assassin.
Modify a weapon.
Return to active duty.
Start a character in multiplayer or customize a character in single-player.
Finish the game on Insanity without changing difficulty after leaving Earth.
Overload the shields of 100 enemies.
Finish all multiplayer maps on Gold or all single-player missions on Insanity.
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.
Complete all the Command Center side-missions on Omega.
Free Omega from Cerberus Occupation.
Find the Talon leader.
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.