Here is the full list of all 20 Idol Hands achievements.
Your priests have converted 20 enemy soldiers
Collect 10,000 units of wood
Complete all tutorials
Game completed by winning the final level
Destroy 10 buildings with volcanoes
Throw 5 meteors in a single level
Create 5 volcanoes in a single level
Complete level 5 onwards with only 6 farmers
Complete level 5 onwards with only 5 woodcutters
Kill 200 enemy furlings
Trigger 10 earthquakes in a single level
Throw 20 lightning bolts in a single level
Make it rain 20 times in a single level
Your priest converts his first enemy furling
Complete a level without losing one of your furlings
Create your first army of 10 soldiers
Create your first priest
Expose your first iron ore
Finish "In the Beginning...", the first tutorial level
Play the game for the first time