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