Here is the full list of all 38 Iron Crypticle achievements.
Complete The First Floor On Hard Difficulty
Defeat The Phantom
Defeat 3 Types Of Miniboss
Defeat Madame Tentacles
Use The Atomic Fist 20 Times
Destroy A Fire Bug
Find The Golden Kitty
Defeat A Boss In All Its Incarnations
Defeat Hexapod
Complete An Infestation Room
Collect 1000 points worth of coins
View 20 Item Descriptions In The Ledger
Clear 50 Rooms Of Monsters
Defeat A Boss Without Using A Weapon Pickup
Buy 10 Items In A Shop
Collect All BONUS Letters
Complete 10 Waves In Endless Mode
Collect 1000 Food Items (Increasing Score Type)
Complete The Mud Pits
Defeat The Giant Peepwort
Complete Castle Crushers 3 times
Use 5 Different Scroll Types
Collect 30 Lemons In A Single Game
Get 100 100x8s In A Single Game
Use 10 Different Weapon Types
Get Rainbow Power
Pick Up 10 Hearts In A Single-Player Game Session
Collect Or Buy 5 Stat Increases In A Single Game
Defeat 1000 Monsters
Finish A Regular Room Without Using A Weapon Pickup
Defeat Gnasher
Get The Golden Poop
Defeat A Boss Without Taking Any Damage
Defeat Boulderface
Complete The Graveyard
Find A Map
Complete The Catacombs
Finish A Non-Boss, Non-Empty Room Without Taking Damage