Here is the full list of all 23 Space Hulk: Deathwing - there are Enhanced Edition achievements.
Kill 10,000 enemies
Complete the Devotion branch
Find all the major relics in the main campaign
Complete the Psy branch
Complete the Command branch
Learn Vortex of Doom
Finish a chapter in the main campaign without using a Psygate
Perform 1,111 assists in multiplayer mode or the special missions
Kill a scythe-strain Genestealer
Kill an hybrid psyker
Kill a Broodlord
Unlock all Tactical Terminator abilities in multiplayer
Unlock all of the Apothecary's abilities in multiplayer
Unlock all of the Librarian's capacities in multiplayer
Kill a stalker-strain Genestealer
Unlock all of the Heavy Weapon Support's abilities in multiplayer
Unlock all Assault Terminator's abilitiess in multiplayer
Kill 666 enemies
Kill a warrior-strain Genestealer
Learn Inferno
Lock a door aboard the Olethros
Destroy a door aboard the Olethros
Use the Psygate