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