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