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