Here is the full list of all 38 Kingdom Elemental achievements.
Each unit that almost dies in a round
Completed a round without any hero deaths.
Completed a round with only one hero surviving.
Completed a round with out a hero getting hurt.
Resurrected all units who die in a round.
Healed all damage taken in a round.
Feigned death with no other heroes left.
Completed a round without using at least 60 gold and using less then 9 units.
Resurrected a single hero more then once.
Completed a round using just one hero.
Completed round with unspent skill points.
Killed two or more enemies with holy bolt.
Completed a round with only Archers.
Completed a round with only Swordsmen.
Completed a round with only Necros.
Completed round with only Druids.
Completed a round with only Monks.
Completed a round with only Bards.
Completed a round with only Paladins.
Completed a round with all Pirates.
Completed a round with only Elementalists.
Completed a level without any hero deaths.
Completed a level without any heroes getting hurt.
Healed all damage taken by heroes in a entire level.
Completed a level without any defeats.
Resurrected all units who died in the entire level.
Did not use any Priests or Paladins in an entire level.
Did not use any healing in entire level.
Defeated at least twenty times.
Defeated at least fifty times.
Defeated at least one hundred times.
Completed game without any defeats.
Summoned at least ten Familiars.
Let at least ten Familiars die.
Raised at least ten Skeletons.
Raised at least twenty Skeletons.
Raised at least thirty Skeletons.
Received all nine hero awards.