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