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