Here is the full list of all 23 Space Hulk: Deathwing achievements.
Complete Psy branch
Kill 10,000 enemies
unlock all Assault Terminator's capacities in multiplayer
unlock all Librarian's capacities in multiplayer
unlock all Tactical Terminator's capacities in multiplayer
Finish a chapter without using a Psygate
unlock all Heavy weapon support's capacities in multiplayer
unlock all Apothecary's capacities in multiplayer
Learn Vortex of Doom
Kill a Broodlord
Kill an hybrid psyker
Kill a Genestealer's assault strain
Kill a Genestealer's warrior strain
Kill a Genestealer's stalker strain
Kill 666 enemies
Learn Inferno
Hack a door
Destroy a door
Use the Psygate
Complete Devotion branch
Complete Commandement branch
Find all the relics
Make 1111 assists