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