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