Full list of all 62 Mass Effect 2 achievements worth 1,355 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 5 DLC packs containing 12 achievements worth 355 Gamerscore.
Complete the game on the "Insanity" difficulty level without changing the setting
Complete Mass Effect 2 twice, or complete it once with a character imported from Mass Effect 1
Keep your team alive through the suicide mission
Reach Level 30 with one character
Save humanity throughout the galaxy from certain annihilation
Survive suicide mission
Use the Omega 4 Relay
Successfully pursue a relationship with a teammate
Hack a geth collective
Obtain geth technology
Gain the loyalty of the Assassin
Fully upgrade a weapon
Help the Justicar resolve her mission
Gain the loyalty of the quarian
Successfully recruit the Assassin
Successfully recruit the Justicar
Successfully recruit the quarian
Complete the investigation of a derelict alien vessel
Gain the loyalty of the Cerberus Officer
Kill enemies with 5 different heavy weapons during the game
Disrupt the shields of 25 enemies
Shoot and kill 20 enemies while they're knocked back by a punch
Gain the loyalty of the krogan
Thresher Maw defeated
Gain the loyalty of the Professor
Incinerate the armor of 25 enemies
Gain the loyalty of Archangel
Gain the loyalty of the biotic Convict
Hit 20 different targets with multiple biotic powers to combine the effects
Evolve any power
Gain the loyalty of the Cerberus Operative
Defend a human colony from attack
Warp the barriers of 25 enemies
Successfully recruit the biotic Convict
Successfully recruit the krogan
Complete 5 missions discovered by scanning unexplored worlds
Visit 100% of the planets in an unexplored cluster
Obtain 10 technology upgrades
Complete a mission discovered by scanning an unexplored world
Complete any research project in the Normandy's laboratory
Successfully recruit Archangel
Successfully recruit the Professor
Make 20 enemies scream as they fall or are set on fire
Unlock 15 new Mass Effect 2 codex entries
Retrieve mineral resources by scanning and probing a planet in the galaxy map
View all advanced combat training videos at Shepard's private terminal.
Perform 30 headshot kills with any weapon on humanoid targets
Return to active duty
Personalize your armor in your quarters on the Normandy
Save your crew from an overwhelming attack
Gain the loyalty of the thief
Successfully shut down the rogue VI in Project Overlord
Collect 6 Cerberus data packets scattered across Aite
Reminisce with Liara on the Normandy
Use all information terminals in the Shadow Broker’s stronghold
Complete the Shadow Broker Mission pack on Hardcore or Insanity
Confront the Shadow Broker
Defeat the Shadow Broker’s Assassin
Gain the loyalty of the mercenary
Survive all five waves in the battle for Object Rho
Complete the Arrival DLC pack
Rescue Dr. Amanda Kenson without attracting hostile attention