Here is the full list of all 20 A Handful of Keflings achievements.
Build a house from scratch.
Build 25 houses in one game.
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 a storage building.
Build three storage buildings of one type, then fill them up.
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
Build a Primary School.
Build a Secondary School.
Build a University.
Upgrade a mine.
Upgrade 20 mines in one game.
Create a Metal Mine.
Create 20 Metal Mines in the same game.
Recycle some junk.
Recycle half of the junk found in the world.
Recycle all of the junk found in the world.