Full list of all 50 Legendary achievements worth 1,000 gamerscore. It takes around 60-80 hours to unlock all of the achievements on Xbox 360.
Played 200 ranked Multiplayer matches
Won 50 ranked Multiplayer matches
Was first place in kills in 10 ranked Multiplayer matches in a row
Filled 50% of your team's Monster Machine with Animus in a ranked 4v4 Multiplayer match
Killed 10 Werewolves in a ranked Multiplayer match without being killed
Killed 10 enemy players in a ranked Multiplayer match without being killed
Ranked 4x4, max Animus match: filled 25% of machine, killed 10 players, 10 werewolves, won match
Fired every weapon available in any ranked Multiplayer match
Collected all PDA pick-ups
Caused Minotaur to destroy all Graveyard wall sections in Episode 5
Looked at all "The Great Langtini" posters littering Times Square in Episode 3
Survived a ranked 4v4 Multiplayer game without being killed
Ran all Council Base lab experiments in Episode 6
Completed game on Easy difficulty
Completed Episode 8
Freed Vivian from captivity in Episode 8
The Lead Designer apologizes for writing the terrible pun "DouBull TrouBull" - have some points
Survived the double Minotaur attack in Episode 8
Completed Episode 7
Took out the power to the Black Order outpost in Episode 7
Caused the crane to drop the metal beams in Episode 7
Completed Episode 6
Collected 1/2 of PDA pick-ups
Started and finished a ranked Multiplayer match
Shot down the low flying Griffons in Episode 6
Fired all 8 projectile weapons in Single Player at least once
Changed the frequency of an Aniform Control Device in Single Player
Completed Episode 5
Defeated the Griffon in Episode 5
Defeated the Minotaur in Episode 5
Completed Episode 4
Eavesdropped on the Black Order as they caged up a Werewolf in Episode 4
Defeated the first Alpha Werewolf in Episode 4
Destroyed a Blood Spider Queen in Episode 4
Completed Episode 3
Destroyed the Giant Golem in Episode 3
Escaped the Nari-possessed vending machine room in Episode 3
Was stepped on by the Giant Golem in Episode 3
Completed Episode 2
Found the Black Order-eliminating electric switch in Episode 2
Unlocked the warehouse exit in Episode 2
Used the Animus Pulse ability 10 times
Killed 25 enemies with the Fire Axe in Single Player
Completed Episode 1
Created a ramp with the soda machine using your pistol in Episode 1
Chopped your way out of the Internet Café with the Fire Axe in Episode 1
Extinguished the doorway fire using the water valve in Episode 1
Bypassed the electronic lock in Episode 1
Complete game on Normal difficulty
Complete game on Hard difficulty