Complete the following achievements to unlock Xbox Live Gamerscore points.

Missing in Action (5 points): Save your crew from an overwhelming attack.
Very Elusive (10 points): Return to active duty.
The Convict (10 points): Successfully recruit the biotic Convict.
The Krogan (10 points): Successfully recruit the krogan.
The Archangel (10 points): Successfully recruit Archangel.
The Professor (10 points): Successfully recruit the Professor.
The Quarian (10 points): Successfully recruit the quarian.
The Justicar (10 points): Successfully recruit the Justicar.
The Assassin (10 points): Successfully recruit the Assassin.
Friend or Foe (10 points): Obtain geth technology.
Colony Defense (25 points): Defend a human colony from attack.
The Prodigal (10 points): Gain the loyalty of the Cerberus Officer.
Ghost of the Father (10 points): Gain the loyalty of the Cerberus Operative.
Catharsis (10 points): Gain the loyalty of the biotic Convict.
Battlemaster (10 points): Gain the loyalty of the krogan.
Fade Away (10 points): Gain the loyalty of Archangel.
The Cure (10 points): Gain the loyalty of the Professor.
Treason (10 points): Gain the loyalty of the quarian.
Doppelganger (10 points): Help the Justicar resolve her mission.
Cat's in the Cradle (10 points): Gain the loyalty of the Assassin.
A House Divided (10 points): Hack a geth collective.
Ghost Ship (25 points): Complete the investigation of a derelict alien vessel.
Suicide Mission (50 points): Use the Omega 4 Relay.
Mission Accomplished (125 points): Save humanity throughout the galaxy from certain annihilation.
Against All Odds (15 points): Survive suicide mission.
Insanity (75 points): Complete the game on the "Insanity" difficulty level without changing the setting.
No One Left Behind (75 points): Keep your team alive through the suicide mission.
Long Service Medal (75 points): Complete Mass Effect 2 twice, or complete it once with a character imported from Mass Effect 1.
Paramour (50 points): Successfully pursue a relationship with a teammate.
Head Hunter (10 points): Perform 30 headshot kills with any weapon on humanoid targets.
Brawler (10 points): Shoot and kill 20 enemies while they're knocked back by a punch.
Big Game Hunter (10 points): Thresher Maw defeated.
Tactician (10 points): Hit 20 different targets with multiple biotic powers to combine the effects.
Master at Arms (15 points): Kill enemies with 5 different heavy weapons during the game.
Merciless (10 points): Make 20 enemies scream as they fall or are set on fire.
Overload Specialist (15 points): Disrupt the shields of 25 enemies.
Warp Specialist (15 points): Warp the barriers of 25 enemies.
Incineration Specialist (15 points): Incinerate the armor of 25 enemies.
Operative (15 points): Complete a mission discovered by scanning an unexplored world.
Agent (50 points): Complete 5 missions discovered by scanning unexplored worlds.
Prospector (5 points): Retrieve mineral resources by scanning and probing a planet in the galaxy map.
Explorer (10 points): Visit 100% of the planets in an unexplored cluster.
Power Gamer (10 points): Reach Level 30 with one character.
Scholar (15 points): Unlock 15 new Mass Effect 2 codex entries.
Technician (15 points): Obtain 10 technology upgrades.
Weapon Specialist (15 points): Fully upgrade a weapon.
Scientist (10 points): Complete any research project in the Normandy's laboratory.
Fashionista (5 points): Personalize your armor in your quarters on the Normandy.
Power Full (15 points): Evolve any power.
Highly Trained (15 points): View all advanced combat training videos at Shepard's private terminal.