Here is the full list of all 40 Archvale achievements.
Equip a shark cap and mermaid tail.
Store over 10,000 gold in the bank.
Defeat the Old King.
Reconstruct the gateway to Archvale.
Obtain Avarn's Sword.
Collect all Heart Containers.
Collect all healing flasks.
Defeat the Banished Executioner.
Defeat the Colossal Skullbot.
Defeat the Sunken Queen.
Cash in 10 treasures.
Collect every badge.
Complete every trial.
Defeat the Rotted King.
Assemble the Arch Lexicon.
Defeat the Grove's Blight.
Obtain the best potion recipe.
Craft 30 items.
Survive the ritual of the Molten Rift.
Fully upgrade a weapon.
Defeat Frankenslime.
Defeat the Exiled Wizard.
Perform five consecutive dashes without stamina recharging.
Complete half of your badge collection.
Defeat the Soul Serpent.
Destroy the barrier guarding Tanglegrove.
Enter the Twisted Caverns.
Defeat the Ghost Crab.
Defeat the Fallen Pharaoh.
Defeat 1000 enemies.
Own 8 hearts.
Defeat Mongo.
Restore 10 fountains.
Defeat the Queen Duneworm.
Die.
Defeat the Great Slime.
Obtain an improved healing recipe.
Defeat Maxilla.
Complete your first trial.
Find the village of Timberwell.