Here is the full list of all 51 Call of Duty: Ghosts Multiplayer achievements.
Kill a Gargoyle with the Vanguard in Awakening in Regular or Hardcore difficulty.
Kill 50 Cryptids with the Venom-X weapon in Nightfall in Regular or Hardcore difficulty.
Complete the final Ancestor with at least 1 relic in Regular or Hardcore difficulty.
Kill the final Ancestor with a relic active in Hardcore difficulty.
Kill the final 3 Ancestors within 10 seconds of killing the first Ancestor in Regular or Hardcore difficulty.
Escape Awakening using two Relics in Regular or Hardcore difficulty.
Kill the Breeder while using a Relic in Nightfall in Regular or Hardcore difficulty.
Complete all challenges and kill the Breeder in Nightfall in Regular or Hardcore difficulty.
Hit an Ancestor with a Hypno Knife in Regular or Hardcore difficulty.
Escape using a relic.
Find all 7 story related intel files in Exodus.
Kill a Rhino with only a pistol in Nightfall in Regular or Hardcore difficulty.
Scavenge 40 items in a single game.
Complete every challenge and the final Ancestor encounter in Regular or Hardcore difficulty.
Complete the final Ancestor encounter in Regular or Hardcore difficulty.
Kill 3 aliens with a single shot from the NX-1 Disruptor in Regular or Hardcore difficulty.
Complete any outpost by activating all of the generators in Regular or Hardcore difficulty.
Kill the Kraken for the first time in Mayday in Regular or Hardcore difficulty.
Complete all Challenges and escape Awakening in Regular or Hardcore difficulty.
Kill the Breeder for the first time in Nightfall in Regular or Hardcore difficulty.
Kill the Breeder in less than 5 minutes in Nightfall in Regular or Hardcore difficulty.
Find all of the Intel in Awakening.
Kill 15 Seeder Turrets in one game in Mayday in Regular or Hardcore difficulty.
Kill 5 Phantoms in one game in Regular or Hardcore difficulty.
Gain access to the Facility in Nightfall in Regular or Hardcore difficulty.
Escape Awakening for the first time in Regular or Hardcore difficulty.
Extend the bridge in Awakening in Regular or Hardcore difficulty.
Get past the first gate in Awakening in Regular or Hardcore difficulty.
Escape with all four players
Complete all Extinction challenges and escape.
Reach the exfil chopper with 1 minute and 30 seconds or more remaining on the clock.
Gain access to the Compound area in Nightfall in Regular or Hardcore difficulty.
Escape 1st time
Make it to the cabin.
Reach the top deck in Mayday in Regular or Hardcore difficulty.
Reach the cargo area in Mayday in Regular or Hardcore difficulty.
Get 50 kills with the electric fence and fire traps in a single game.
Reach round 20 in Safeguard.
Made it to the city.
Find all the intel hidden in Nightfall.
Complete the Egg-Stra XP challenge and then destroy a hive in the Onslaught DLC package.
Kill the Kraken using a Relic in Mayday in Regular or Hardcore difficulty.
Complete all Challenges and kill the Kraken in Mayday in Regular or Hardcore difficulty.
Find all of the Intel in Mayday.
Use a hypno trap to turn a Rhino friendly in Mayday in Regular or Hardcore difficulty.
Complete the Egg-Stra XP challenge and then destroy a hive in the Devastation DLC package.
Successfully build all of the Schematics in Mayday in Regular or Hardcore difficulty.
Complete the Egg-Stra XP challenge and then scan an obelisk in the Invasion DLC package.
Kill 5 cryptids with the Ark attached to every compatible weapon in Awakening in Regular\Hardcore.
Escape Awakening with each of the four classes in Regular or Hardcore difficulty.
Complete the Egg-Stra XP challenge and then activate a generator in the Nemesis DLC package.