Here is the full list of all 31 Iron Fisticle achievements.
Collect all hint books
Get the golden turd
Collect a giant piece of cake
Get the golden bananas
Get garlic breath
Collect 100 treasures
Complete a room when entering with only 1 health
Complete the game
Reach max level
Kill 10 enemies using dash
Collect 10 golden goblets
Collect 1000 coins
Kill a golem
Make lemonade
Complete the third floor
Collect all rainbow gems
Collect 100 items in the ledger
Collect 5 diamonds
Complete the second floor
Collect all letters spelling B-O-N-U-S
Open 100 chests (any type)
Complete The Catacombs
Level up ten times
Kill 1000 Frankies
Complete the bonus game
Complete the first floor
Buy a gold item in the shop
Complete The Graveyard
Complete a room without losing any health
Complete the first room
Level up once