Here is the full list of all 86 Earthfall achievements.
Finished any campaign on the hardest difficulty
Complete the Radio Silence mission on Overwhelming difficulty
Kill 45 Sappers
Kill 600 aliens with headshots
Complete the Sunnyvale mission on Overwhelming difficulty
Complete the Data Recovery mission on Overwhelming difficulty
Complete the Breakdown mission on Overwhelming diffculty
Complete the Supply Run mission on Overwhelming difficulty
Complete all missions in the Natural Selection campaign
Complete the Hatchery Finale Center mission
Kill 500 aliens with the SW22
Complete the Hatchery Center mission
Kill a Sapper with fire
Complete the Dam mission
Deployed 100 Barrier Kits
Kill 20 Sappers
Complete the Warehouse mission
Complete the Revelation mission
Complete all missions in the Invasive Species campaign
Complete the Radio Silence mission
Kill 2000 Drones
Complete the Sunnyvale mission
Kill 10 Enragers
Complete the Data Recovery mission
Make it through a mission without being incapacitated
Kill 1000 Drones
Complete the Breakdown mission
Help an incapacitated player up
Use a health item on another player
Shove a Sapper
Initiate a print on a 3D Printer
Restore power to a printer or health station
Deploy a Mounted Gun
Complete the Supply Run mission
Completed a mission using only pistols
Rescue someone from the Whiplash
Killed 25 aliens in 1 minute or less
Rescue someone pinned by the Thresher
Use a health item on yourself
Kill an alien with a melee weapon
Deploy a Barrier Kit
Kill 35 Threshers
Kill 10 Whiplashes
Kill 5 Beasts
Kill 999 Blackouts
Kill 600 or more Drones by shooting them through the brain
Kill 700 aliens with a melee weapon
Deploy 25 mounted guns
Kill 150 aliens with grenades
Save 40 incapacitated players
Save 40 unconscious players
Win a game with high accuracy
Kill 8000 Drones
Kill 180 Sappers
Kill 300 Threshers
Kill 80 Whiplashes
Kill 60 Beasts
Killed 9999999 Blackouts
Kill 1000 aliens with the MP5
Kill 1000 aliens with the Berg 930
Kill 1000 aliens with the AK47
Kill 750 aliens with the Glintec
Kill 1000 aliens with the AK67
Kill 750 aliens with the Vendetta
Kill 1500 aliens with the Combat CVA
Kill 1500 aliens with the EF18
Kill 1000 aliens with the Harbinger
Kill 1000 aliens with the Reaper
Shove a Thresher out of the air
Kill 75 Threshers
Kill 20 Whiplashes
Kill 15 Beasts
Killed 99999 Blackouts
Kill 400 aliens with a Mounted Gun
Save 40 pinned players
Heal 20 players
Heal 60 players
Killed 5 aliens with one shot
Killed 50 consecutive aliens with headshots or brainshots
Kill 2500 aliens with melee weapons
Complete the Revelation mission on Overwhelming difficulty
Complete the Dam mission on Overwhelming difficulty
Complete the Warehouse mission on Overwhelming difficulty
Kill 1000 aliens with the Valkyrie
Complete the Hatchery mission on Overwhelming difficulty
Complete the Hatchery Finale mission on Overwhelming difficulty