Here is the full list of all 42 Rebuild 3: Gangs of Deadsville achievements.
Finish any city on Hard difficulty
Kill 100,000 zombies cumulatively
Complete the Gangs of Deadsville questline
Complete the final scenario city
Get any survivor to defense level 20 (includes equipment)
Equip every survivor with a gun
Equip a Rocket Launcher
Be allies with every faction in the city
Light off Fireworks
Have 5 hospitals, 10 medkits, and 100 medicine at once
Have a survivor with 10 in every skill
Equip 10 animals
Complete the Return to New York questline
Use 50 bath salts in one game
Repair an airplane and fly away
Declare peace with a faction
Fully infect the Dahlias with your cultists
Have 50% of survivors become cultists
Complete the Pig Farmer questline
Produce 100 items in the workshop cumulatively
Kill 10,000 zombies cumulatively
Become allies with any faction
Find 100 items while scavenging cumulatively
Destroy every faction on the map
Destroy any faction
Finish any city by day 50
Fix a Power Plant
Have 365 food at once
Complete every research project
Have 100 survivors at once
Generate a surplus of 50 food per day from farms
Complete scenario city 1
Finish any city on any difficulty
Reclaim the entire city
Get any survivor to level 10 in some skill
Build a City Hall
Kill 1000 zombies cumulatively
Kill 100 zombies cumulatively
Finish any city on Impossible difficulty
Become Gustav's friend and get his special deals
Eat enough people to be considered evil cannibals
Discover the true origin of the disease