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