Here is the full list of all 55 Ancient Dungeon achievements.
Raise your merchant discount to 60%.
Traverse The Forgotten Library without taking any damage.
Traverse The Luminous Mines without taking any damage.
Escape The Ancient Dungeon after re-entering three times.
Traverse The Beast's Cradle without taking any damage.
Traverse The Infested Dungeon without taking any damage.
Defeat one hundred aberrant enemies.
Carry more than two hundred fifty coins during a single delve.
Acquire more than five full hearts of health.
Escape The Ancient Dungeon after re-entering once.
Escape The Ancient Dungeon after re-entering twice.
Damage The Beast with the Mercenary's Armament.
Win big on The Merchant's slot machine.
Carry more than twenty keys during a single delve.
Lower your merchant discount to -100%.
Damage The Beast with the Assassin's Armament.
Damage The Beast for the first time.
Defeat a Possessed Armor.
Explore two hundred fifty rooms within The Ancient Dungeon.
Use The Blacksmith's Anvil to augment a weapon.
Destroy a Sacrifice Statue.
Discover a secret room in the ceiling.
Acquire four items from shops during a single delve.
Discover a secret room in the wall.
Defeat a boss enemy with a single strike.
Strike enemies with a ranged weapon twenty-five times in a row without missing.
Use a Bandit Box at least twenty times during a single delve.
Defeat a Mad Merchant.
Deal at least twenty-five damage with a single strike.
Enter The Ancient Dungeon for the first time.
Overcome a Challenge Chest's trial.
Defeat a Chest Mimic.
Traverse The Overgrown Gatehouse without taking any damage.
Acquire three highly powerful items during a single delve.
Destroy one thousand pots.
Discover (almost) all items.
Escape The Ancient Dungeon without consuming any food items.
Use a Contracting Orb to shrink yourself.
Eat every type of food item during a single delve.
Defeat a Golden Slime.
Escape the dungeon without obtaining any upgrade items.
Damage The Beast with the Mercenary's Armament in hard mode.
Damage The Beast with the Assassin's Armament in Hard Mode
Escape the Ancient Dungeon without entering a shop.
Escape the Ancient Dungeon in under twenty minutes.
Fully augment the Assassin's Armament.
Fully augment the Mercenary's Armament.
Consume a food item made of gold.
Throw a dragonfruit into a pit.
Complete the delve of every Sealed Soul.
Complete 3 unique sealed soul delves
Challenge and destroy a boss with only a half-heart of health
Open 250 chests
Escape The Ancient Dungeon with a difficulty modifier of 2.25
Escape The Ancient Dungeon with a difficulty modifier of 3.00