Here is the full list of all 32 Stirring Abyss achievements.
Defeat the Captain Ascendant.
Deal 150 damage with one critical attack.
Unlock one of the top-level nodes on the Biological track of the Enigma Board.
Have a single diver undergo four Mutations.
Recover the arming code for the Soviet nuclear bomb.
Defeat the Gatekeeper.
Inspect a dead Soviet Diver.
Unlock one of the top-level nodes on the Mechanical track of the Enigma Board.
Kill five or more enemies in a single turn.
Defeat the First to Hunger.
Inspect a dead Stalking Tentacle.
Pump every section of the Salem.
Inspect a dead Harvester.
Inspect a dead Fathom Seer.
Inspect a dead Voidspawn.
Deal 250 damage to enemies in a single turn.
Inspect a dead Vessel.
Inspect a dead Infected Pod.
Mutate one of your divers.
Have an enemy kill another enemy.
Inspect a dead Murkfiend.
Inspect a dead Spineskulker.
Inspect a dead Burst Pod.
Inspect a dead Scyphozoa.
Detonate the Soviet nuclear bomb.
Complete the game on Hard difficulty.
Earn 20,000 score on Endless Mode.
Uncover 1,000 Clues.
Kill 500 enemies.
Kill one of your divers with friendly fire.
Unlock one of the top-level nodes on the Eldritch track of the Enigma Board.
Use the Profane Chapel to resurrect a dead diver.