Here is the full list of all 32 Another Crab's Treasure achievements.
Learn all adaptations.
Fully upgrade Kril's fork.
Get your shell back.
Defeated Firth.
Try on every shell in the game.
Find a certain hero's helmet.
Shoot a crab with a gun.
Defeated the Consortium.
Defeated the Curdled Carbonara Connoisseur.
Defeated Praya Dubia.
Defeated Camtscha (For real.)
Defeated Camtscha.
Defeated Inkerton.
Defeated Petroch.
Defeated Roland.
Unlock all skills on the Path of The Predator.
Defeated Voltai.
Unlock all skills on the Path of The True Crab.
Defeated the Ceviche Sisters.
Defeated the Scuttling Sludge Steamroller.
Unlock all skills on the Path of The Hermit.
Defeated Topoda.
Defeated Pagurus.
Defeated Heikea.
Fall off a cliff.
Defeated the Diseased Lichenthrope.
Purchase some insurance.
Start the treasure hunt.
Defeated the Royal Shellsplitter.
Defeated Magista.
Defeated a miniboss.
Defeated Nephro.