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