Here is the full list of all 35 The Last Stand: Aftermath achievements.
Complete the main quest line
Died 10 times
Kill an Armored Charger
Kill a Flamer
Reach Hell
Lower the bridge in Leighton City
Use Antiviral 25 times
Craft 25 items at a crafting stations
Collect 100 Knowledge
Kill a Spitter
Reach The Sunken City
Activate the radio tower
Craft an improvised weapon
Survive in No Man's Land
Kill 1000 Infected
Kill a Leaper
Reach The Mountains
Open the gates at the HERC checkpoint
Kill a Burster
Kill a Charger
Craft an item at a crafting station
Purchase an item from the travelling merchant
Discover the modified HERC device
Reach Level 10
Reach Level 50
Reach Level 100
Spend Knowledge points to max out a skill upgrade
Trigger a trap, with fatal consequences
Survive a Horde
Kill a Volunteer
Acquire a mutation
Interact with a Supply Cache
Complete the tutorial
Complete 5 Runs
Collect 25 Supply Bags