Here is the full list of all 21 Debris achievements.
Do you trust ALTA?
Make it through the dark fish delta in Dark without taking damage.
Enable the scenic screenshot mode.
Find a secret irradiated montipora and dive into ALTA's archives.
Make your presence known in Shock.
Do not die alone.
Endure a somatic delusion.
Endure a grandiose delusion.
Endure a persecutory delusion.
Endure a delusion of control.
Endure each delusion.
Make it through Light and Teeth without taking damage.
Make it through the bobbit lair without taking damage.
Make it through the dark fish delta in Flow without taking damage.
Let's hope you're right.
Find half of the secret montipora.
Find every secret montipora throughout the cave network.
Complete the montipora archive in every reality.
Winner winner frozen dinner. Find the frozen fish.
Find the dead fish who ate an urchin.
Not all voices are against you. Find the Hall of Voices.