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