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There are 46 achievements in the Xbox 360 version of Mass Effect, worth a total of 1050 

Picture	Achievement	Description
	Medal of Honor	Complete 1 Mass Effect Playthrough on any setting.	100
	Medal of Heroism	Complete Feros.	25
	Distinguished Service Medal	Complete Eden Prime.	25
	Council Legion of Merit	Complete Virmire.	25
	Honorarium of Corporate Service	Complete Noveria.	25
	Long Service Medal	Complete 2 Mass Effect Playthroughs on any setting.	25
	Distinguished Combat Medal	Complete 1 Mass Effect playthrough on the Hardcore difficulty setting. Do not change the setting..	25
	Medal of Valor	Complete 1 Mass Effect playthrough on the Insanity difficulty setting. Do not change the setting..	50
	Pistol Expert	Register 150 Pistol Kills.	10
	Shotgun Expert	Register 150 Shotgun Kills.	15
	Assault Rifle Expert	Register 150 Assault Rifle Kills.	15
	Sniper Expert	Register 150 Sniper Rifle Kills.	15
	Lift Mastery	Use biotic Lift 75 times.	15
	Throw Mastery	Use biotic Throw 75 times.	15
	Warp Mastery	Use biotic Warp 75 times.	15
	Singularity Mastery	Use biotic Singularity 75 times.	15
	Barrier Mastery	Use biotic Barrier 75 times.	15
	Stasis Mastery	Use biotic Stasis 75 times.	15
	Damping Specialist	Use Damping Field 75 times.	15
	AI Hacking Specialist	Use AI Hacking 75 times.	15
	Overload Specialist	Use Shield Overload 75 times.	15
	Sabotage Specialist	Use Sabotage 75 times.	15
	First Aid Specialist	Use medi-gel 150 times.	15
	Neural Shock Specialist	Use Neural Shock 75 times.	15
	Scholar	Find all primary Alien: Council Races, Extinct Races and Non-Council Races codex entries.	25
	Completionist	Complete the majority of the game.	25
	Tactician	Complete playthrough with shield damage greater than health damage.	25
	Medal of Exploration	Land on an uncharted world.	50
	Rich	Exceed 1,000,000 Credits .	25
	Dog of War	Register 150 organic enemy kills.	25
	Geth Hunter	Register 250 synthetic enemy kills.	25
	Soldier Ally	Complete the majority of the game with the Alliance soldier squad member.	20
	Sentinel Ally	Complete the majority of the game with the Alliance sentinel squad member.	20
	Krogan Ally	Complete the majority of the game with the krogan squad member.	20
	Turian Ally	Complete the majority of the game with the turian squad member.	20
	Quarian Ally	Complete the majority of the game with the quarian squad member.	20
	Asari Ally	Complete the majority of the game with the asari squad member.	20
	Power Gamer	Reach 50th level with one character.	20
	Extreme Power Gamer	Reach 60th level with one character.	50
	Renegade	Accumulate 75% of total Renegade points.	15
	Paragon	Accumulate 75% of total Paragon points.	15
	Paramour	Complete any romance subplot.	10
	Spectre Inductee	Become a Spectre.	15
	Charismatic	Use Charm or Intimidate to resolve an impossible situation.	10
	Search and Rescue	Locate Dr. T'soni in the Artemis Tau cluster.	10
	Colonial Savior	Complete the "Bring down the Sky" DLC.	50