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