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