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