Here is the full list of all 41 Ratopia achievements.
Make trade agreement.
Middle class appeared in the city.
Find other cities.
Reach prosperity level 4
Survive a year in Hard difficulty.
Experienced Winter's end.
Experienced Autumn's end.
Build a rail in the city.
Experienced Summer's end.
Order soldeirs to escort.
Activate a new policy.
Build a decorative structure.
Activate a shrine.
Rest on a Royal Bed
Experienced Spring's end.
Assigne a ratizen to a job.
Research a blueprint.
Destroy infected's grave.
Accept a migrant.
Bury a dead to a grave.
Place a citizen in a group.
Use a loan.
Upper class appeared in the city.
Reach prosperity level 7
Build a huge monument.
Keep at least 50 middle class for 12 days.
Keep at least 50 upper class for 12 days.
Saves 99,999 Pia.
Build Merchant Monument.
Build Noble Monument.
Reach 100 population
Produce an equipment
Change the style of the leader
Enter the dungeon
Destroy Weasel Barracks
Supply electricity to the city for the first time.
Assemble a Ratron at the Ratron Assembly Plant
Conquering the Forgotten Mine
Conquering the Barbaric Palace
Build Scientist Monument
Operate more than 30 Ratrons