There's a dialog option at the very start of the game when you are in the communications room with Nihlus and Captain Anderson. I believe it's when Captain Anderson mentions that Systems Alliance found a Prothean Beacon on Eden Prime, one of the following dialog options allows you to ask about the Protheans.
Here's an achievement list:
Entire Game
* Medal of Honor (100) – Complete 1 Mass Effect playthrough on any difficulty.
o Unlocks Hardcore difficulty setting and unlocks character levels 51-60.
* Long Service Medal (25) – Complete 2 Mass Effect playthroughs on any difficulty.
o Weapon damage increased by 5%
* Completionist (25) – Complete the majority of the game.
o Experience rewards increase by 5%
* Tactician (25) – Complete playthrough with shield damage greater than health damage.
o Shield strength increases by 10%
By Planet
* Medal of Heroism (25) – Complete Feros.
* Distinguished Service Medal (25) – Complete Eden Prime.
* Council Legion of Merit (25) – Complete Virmire.
* Honorarium of Corporate Service (25) – Complete Noveria.
By Difficulty
* Distinguished Combat Medal (25) – Complete 1 Mass Effect playthrough on the Hardcore difficulty setting. Do not change the setting.
o Unlocks a gamer pic of Saren for use in your profile and unlocks Insanity difficulty setting.
+ You do not need to start a new career to receive this achievement, just change it before the end of Eden Prime and don't touch it again.
* Medal of Valor (50) – Complete 1 Mass Effect playthrough on the Insanity difficulty setting. Do not change the setting.
o Unlocks a "N7" gamer pic for use on your profile.
+ You do not need to start a new career to receive this achievement, just change it before the end of Eden Prime and don't touch it again.
By Experience
* Power Gamer (20) – Reach 50th level with one character (Requires 238,100 xp.)
o All experience rewards increase by 10%
* Extreme Power Gamer (50) – Reach 60th level with one character (Requires 862,100 xp.)
o All experience rewards increase by 5%
By Story Event
* Paramour (10) – Complete any romance subplot.
* Spectre Inductee (15) – Become a Spectre.
* Search and Rescue (10) – Locate Dr. T'soni in the Artemis Tau cluster.
* Charismatic (10) – Use Charm or Intimidate to resolve an impossible situation.
o Complete the Virmire: Wrex and the Genophage assignment with Wrex surviving.
o This achievement can also be earned by convincing Saren to shoot himself in the endgame battle. The game, however, concludes normally.
By Alignment
* Renegade (15) – Accumulate 75% of total Renegade points.
* Paragon (15) – Accumulate 75% of total Paragon points.
By Registered Kills
* Dog of War (25) – Register 150 organic enemy kills.
o Increase health by 10%
* Geth Hunter (25) – Register 250 synthetic enemy kills.
o Increase shield strength by 10%
By Party Member
Party Member Achievement Guide
* Soldier Ally (20) – Complete the majority of the game with the Alliance soldier squad member Ashley Williams.
o Damage Reduction improves by 10%
+ Tied to Completionist achievement, must complete 75% of the game with said character.
* Sentinel Ally (20) – Complete the majority of the game with the Alliance sentinel squad member Kaidan Alenko.
o Lift and Throw recharge time improve by 10%
+ Tied to Completionist achievement, must complete 75% of the game with said character.
* Krogan Ally (20) – Complete the majority of the game with the krogan squad member Urdnot Wrex.
o Regenerate 1 hp per second (main character only)
+ Tied to Completionist achievement, must complete 75% of the game with said character.
* Turian Ally (20) – Complete the majority of the game with the turian squad member Garrus Vakarian.
o Damping and Overload recharge time improve by 10%
+ Tied to Completionist achievement, must complete 75% of the game with said character.
* Quarian Ally (20) – Complete the majority of the game with the quarian squad member Tali'Zorah nar Rayya.
o Sabotage and AI Hacking recharge time improve by 10%
+ Tied to Completionist achievement, must complete 75% of the game with said character.
* Asari Ally (20) – Complete the majority of the game with the asari squad member Liara T'Soni.
o Barrier and Singularity recharge time improve by 10%
+ Tied to Completionist achievement, must complete 75% of the game with said character.
Miscellaneous
* Scholar (25) – Find all primary Alien: Council Races, Extinct Races and Non-Council Races Codex entries
o Requires pre-Eden Prime dialogue
* Medal of Exploration (50) – Land on an uncharted world.
* Rich (25) – Exceed 1,000,000 Credits.
o Unlocks Spectre weapons at the store within the Normandy and C-Sec Academy; here is a suggested method.
DLC
* Colonial Savior (50) – Complete the Bring Down the Sky Mission.
Talent Use
By Weapon
* Pistol Expert (10) – Register 150 Pistol Kills.
o Marksman duration increased by 25%
* Shotgun Expert (15) – Register 150 Shotgun Kills.
o Unlocks Shotgun for use as a bonus talent
* Assault Rifle Expert (15) – Register 150 Assault Rifle Kills.
o Unlocks Assault Rifle for use as a bonus talent
* Sniper Expert (15) – Register 150 Sniper Rifle Kills.
o Unlocks Sniper Rifle for use as a bonus talent
By Biotic Talents
* Lift Mastery (15) – Use biotic Lift 75 times
o Unlocks Lift for use as a bonus talent
* Throw Mastery (15) – Use biotic Throw 75 times
o Unlocks Throw for use as a bonus talent
* Warp Mastery (15) – Use biotic Warp 75 times
o Unlocks Warp for use as a bonus talent
* Singularity Mastery (15) – Use biotic Singularity 75 times
o Unlocks Singularity for use as a bonus talent
* Barrier Mastery (15) – Use biotic Barrier 75 times
o Unlocks Barrier for use as a bonus talent
* Stasis Mastery (15) – Use biotic Stasis 75 times
o Unlocks Stasis for use as a bonus talent
By Tech Talents
* AI Hacking Specialist (15) – Use AI Hacking 75 times
o Unlocks Hacking for use as a bonus talent
* Damping Specialist (15) – Use Damping Field 75 times
o Unlocks Damping for use as a bonus talent
* Overload Specialist (15) – Use Shield Overload 75 times
o Unlocks Electronics for use as a bonus talent
* Sabotage Specialist (15) – Use Sabotage 75 times
o Unlocks Decryption for use as a bonus talent
* First Aid Specialist (15) – Use medi-gel 150 times
o Unlocks First Aid for use as a bonus talent
* Neural Shock Specialist (15) – Use Neural Shock 75 times
o Unlocks Medicine for use as a bonus talent
Linear Mode
