Here is the full list of all 50 Citizens of Earth achievements. It takes around 25-30 hours to unlock all of the achievements on Windows.
Get all citizens to Lv 30.
Use 150 items.
Use 75 items.
Receive 10,000 damage in combat.
Complete all Photography quests.
Complete all Extermination quests.
Complete all Wanted Poster quests.
Recruit all 40 citizens.
Defeat 1,000 enemies.
Earn $100,000 in the Casino.
Defeat the Secretary Supreme.
Defeat the Alien Commander.
Collect 300 items.
Enroll 9 citizens simultaneously in School.
Defeat the Mishmasher.
Use 25 items.
Defeat Honcho Villa.
Recruit 25 citizens.
Defeat DJ Voodoo.
Defeat Agent D.O.O.M.
Defeat Colonel Cookie.
Find 100 treasures.
Defeat 250 enemies.
Spend $10,000.
Receive 2,500 damage in combat.
Deal 10,000 damage in combat.
Earn $10,000.
Defeat the Hippie Guru.
Ambush 10 enemies in a row.
Collect 100 items.
Get one citizen to Talent Lv 3.
Spend $3,000.
Spend $1,000.
Get one citizen to Lv 20.
Find 45 treasures.
Discover 30 locations.
Defeat the Puppet President.
Earn $3,000.
Discover 20 locations.
Defeat Mr. Mocha.
Receive 500 damage in combat.
Deal 2,500 damage in combat.
Collect 30 items.
Defeat 50 enemies.
Find 15 treasures.
Recruit 5 citizens.
Deal 500 damage in combat.
Earn $1,000.
Discover 10 locations.
Defeat the Opposition Leader.