There is a set of extra Challenges that can be completed by performing certain tasks in the game.

Challenge	How to unlock
Ambassador's Club	Get one citizen to level 20.
Bring it On!	Recieve 10,000 damage in combat.
Budget Cuts	Spend $1,000.
Career Politician	Recruit 25 citizens.
Charitable Donation	Use 150 items.
Diplomat's Club	Get all citizens to level 30.
Early Retirement	Earn $10,000.
Easy Money	Earn $1,000.
Explorer	Discover 10 locations.
Favored To Win	Ambush 10 enemies in a row.
Finders Keepers	Find 15 treasures.
Fundraiser	Earn $3,000.
Globetrotter	Discover 30 locations.
Government Spending	Spend $3,000.
Heavy Hitter	Deal 2,500 damage in combat.
Hoarder	Collect 100 items.
House of Cards	Earn $100,000 in the Casino.
Intelligence Network	Find 100 treasures.
Junior Statesman	Recruit 5 citizens.
Master Bureaucrat	Deal 10,000 damage in combat.
Maximizing You Potential	Get one citizen to Talent Level 3.
Mud Slinger	Deal 500 damage in combat.
New Sheriff In Town	Complete all 10 Wanted Poster quests.
No Citizen Left Behind	Enroll 9 citizens simultaneously in School.
No Pardons For You	Defeat 1,000 enemies.
Odds 'n Ends	Collect 30 items.
Ouchie!	Recieve 500 damage in combat.
Out of My Way	Defeat 50 enemies.
Paparazzi	Complete all Photography quests.
Pick Me Up	Use 25 items.
Presidential Library	Collect 300 items.
Raising the Deficit	Spend $10,000.
Roll Up Your Sleeves	Complete all Extermination quests.
Supply and Demand	Use 75 items.
Trailblazer	Discover 20 locations.
Treasure Hunter	Find 45 treasures.
Walk it Off!	Receive 2,500 damage in combat.
Who's Next	Defeat 250 enemies.
World Leader	Recruit all 40 citizens.