Here is the full list of all 20 A Handful of Keflings achievements.
Upgrade a mine.
Build three storage buildings of one type, then fill them up.
Build a University.
Create a Metal Mine.
Build a Secondary School.
Build 25 houses in one game.
Recycle some junk.
Build a Primary School.
Build a storage building.
Build a house from scratch.
Build the maximum number of houses in one game.
Have 80 keflings working at one time (no waiting keflings).
Build a kingdom full of culture, at least 200 stars worth!.
Build five storage buildings of one type, then fill them up.
Have 500 of any single resource in storage.
Drop the conversion rate for one resource to 2 : 1
Upgrade 20 mines in one game.
Create 20 Metal Mines in the same game.
Recycle half of the junk found in the world.
Recycle all of the junk found in the world.