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