Here is the full list of all 50 Middle-earth: Shadow of Mordor achievements worth 1,000 gamerscore.
Acquire a level 25 Rune.
After an uruk kills you to become a Captain, help him become a Warchief, then kill him.
Brand 5 Bodyguards of a Warchief, turning them against him in combat.
Start a Riot by commanding a Warchief to attack another Warchief.
Complete all Urfael Legend Missions.
Kill The Black Hand.
Kill The Tower.
Brand all 5 Warchiefs.
Save Lithariel's life.
Lift Lady Marwen's curse.
Complete all Outcast Rescue Missions.
Kill the Great White Graug.
Complete all Hunting Challenges.
Make 20 uruks flee by dropping Morgai Fly nests.
Complete all Survivalist Challenges.
Liberate 20 slaves in 300 seconds while riding a caragor.
Successfully complete 4 Hunting Challenges.
Poison a Captain at his own Feast.
Help a Captain survive a Recruitment Power Struggle, and then kill him and all his new recruits.
Perform an Execution on a flaming Berserker.
Use Strike From Above while at least 60 feet above your target.
Complete all Acharn Legend Missions.
Brand a Captain while in combat.
Complete all Azkâr Legend Missions.
Collect 100% of the Ithildin.
Collect 100% of the Artifacts and listen to their memories.
Activate all Forge Towers.
Use the Detonate ability to burn 50 uruks.
Kill all 5 Warchiefs before any uruk take their place.
Kill The Hammer.
Destroy the Monument Gate and topple the statue of Sauron.
Issue a Death Threat, and then successfully kill the target.
Attract caragors with bait 5 times.
Collect 50% of the Ithildin.
Witness the creation of The Rings of Power.
Capitalize on a Warchief's Fear.
Get Ratbag promoted to Warchief.
Eliminate the bodyguards of two Warchiefs, then draw them out and kill them.
Free 5 caragors from cages.
Unlock 3 Sword Rune slots.
Complete a Sword Mission and begin growing the legend of Urfael.
Collect 25% of the Artifacts.
Unlock 2 Bow Rune slots.
Complete a Bow Mission and begin growing the legend of Azkâr.
Unlock 4 Dagger Rune slots.
Complete an Outcast Rescue Mission.
Successfully complete a Survivalist Challenge.
Complete a Dagger Mission and begin growing the legend of Acharn.
Discover some of the Wraith's past.
Make an uruk yours.