Full list of all 21 Warhammer 40,000: Boltgun achievements.
The base game contains 12 achievements, and there is 1 DLC pack containing 9 achievements.
Complete all Chapter III Missions
Complete all Missions on The Emperor Protects Difficulty
Complete all Missions on My Armour is Contempt Difficulty
Complete all Missions on Emperor’s Mercy Difficulty
Complete all Missions on Exterminatus Difficulty
Complete all Chapter II Missions
Defeat a Great Unclean One
Complete all Chapter I Missions
Defeat a Lord of Change
Find all Secrets in Chapter 1
Find all Secrets in Chapter 2
Find all Secrets in Chapter 3