Here is the full list of all 51 The Greatest Penguin Heist of All Time achievements.
Finished Dark Castle
Slayed Hsif, the Penguin Demon
Discovered the Secret of Dark Castle's Painting
Finished Military Base
Finished On a Rail on Hardcore difficulty
Finished Playa Del Sol
Shoot yourself out of a cannon
Finished On a Rail
Finished a heist without being seen
Finished Pongton
You murdered a penguin in cold blood.
You used your hacking capabilities to access a security system.
Finished Research Station on Hardcore difficulty
Finished Pongo City on Hardcore difficulty
Finished Playa Del Sol on Hardcore difficulty
Finished Military Base on Hardcore difficulty
Finished Pongolantis on Hardcore difficulty
Finished The Nile on Hardcore difficulty
Finished Pongo Coal Mine on Hardcore difficulty
Finished Et tu, Bingus on Hardcore difficulty
Finished Research Station
Finished Pongo City
Finished Pongolantis
Finished The Nile
Finished Pongo Coal Mine
Finished Et tu, Bingus
Poop 100 Times
Finished Dark Castle on Hardcore difficulty
Finished Pumpkin Harvest
Finished Pumpkin Harvest on Hardcore difficulty
Finished Research Station in under 30 seconds
Earn 100 000 fish coins from heisting
Reunite a mother and her baby
Finished Pongton on Hardcore difficulty
Die for the first time
Kill 50 penguins in cold blood
Kill 100 penguins in cold blood
Bake 10 pizzas in one game of Pizza Panic
Bake 30 pizzas in one game of Pizza Panic
Play Pizza Panic while dressed as Chef Panguino
Unlock 10 blueprints
Use Mjölnir
"Accidentally" kill the Undercover Scientist in Research Station
Rescue the Potato Lover's Girlfriend
Manage to make a chocolate pizza
Throw 300 punches
Finish Playa del Sol while dressed as Chef Panguino
Find all blueprints in a heist before exfiltrating
Fall into lava inside the temple in The Nile
Noot 1000 times
Remove all signs of life from a heist