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