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