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