To view achievements on Steam, under "Community" click "My profile" then "View all my games", click the game, then "view stats".
Angel of Death: Kill a total of 1000 enemies in all games played combined.
Breacher: Destroy 20 doors with a Chainfist, these can be malfunctioning or not.
Exemplar of the Codex Astartes: Complete any mission without using command points.
Exterminator: Kill 10 genestealers during one turn in the "Exterminate" mission.
For the emperor and Sanguinius!: Complete all chapters of the "The Sin of Damnation" campaign.
Forged in battle: Earn all campaign achievements.
Grant us the strength to prevail: Win close assault against Broodlord.
Honour is my shield: Calistarius survives in the "Escape Route" mission.
Honour Your Wargear: Unjam a malfunctioning storm bolter 40 times.
Light in the darkness: Escape with at least two Terminators before the start of the second wave in "Pitfall" mission.
Our duty is done: Escape with eight or more marines during "Decoy" mission.
Power of the warp: Kill 6 genestealers with one psychic storm.
Pyroclast: Kill 6 genestealers in one shot with the flamer, they must die on the actual shot, deaths from walking through the flames on following turn do not count.
Red Thirst: Have any terminator kill 3 genestealers in melee during one turn, easiest to earn this by placing a melee unique terminator on defense in a position where several gene stealers are close enough to attack only him.
Relic Bearer: The marine that picks up the chalice in "The Artefact" mission must be the one exiting the map with it.
Sever the head and the beast will die: Kill the broodlord in "Unknown Lifeforms" mission.
Slayer of Monsters: Kill 5 Broodlords.
Stand against the tide: Let no terminators die during "Defend" mission.
Stand together or fall alone: No marine may exit the map before all have been put into play in the "Regroup" mission.
Storm of Iron: Kill 30 genestealers with the assault cannon.
Sword of Retribution: Kill 20 Genestealers with the power sword.
The Emperor protects: Survive 15 close combat encounters.
The Emperors Finest: Customize your banner.
The purging flame: Cleanse both rooms in the same turn during "Cleanse And Burn" mission.
There is only war!: Kill 40 000 enemies.
Unbowed and Unbroken: Wake all unconscious Marines and exit the map without losing a single terminator during "Alarm Call" mission.
Victory is nothing more than survival: Survive "Suicide Mission" without any casualties.
Watch the claws: Pass the C.A.T. between at least three terminators during "Rescue" mission.