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