Here is the full list of all 20 Cliff Empire achievements.
Survive 20 waves of Marauders
Reach 7000 population on Earth
Defrost 2000 people
Reach 200 newborn on Earth
The explosion of the nuclear power plant
Critically low ecology
The moment when two warehouses arrive at once
Fly by personal transport when all your cities have a 1000000¢ in total
Destroy 10 buildings in a row
Earn 50000¢
Complete 100% of all researches
Fully load trading barge
More agrarian drones count than ordinary
Get up by elevator of entertainment center
Complete 50% of all researches
Build 10 buildings at once
Complete 25% of all researches
Save 20 buildings from fire