Here is the full list of all 12 Warhammer 40,000: Kill Team achievements.
Complete a mission in co-op mode
Get over 50 kills with each weapon type
Earn a gold Aquila in every survival challenge
Play through each mission with two different Space Marines
Unlock all weapons and ability upgrades
Defeat the Warboss!
Find all the collectables
Kill 5000 enemies in total
Achieve a "Bloodbath" Kill streak
Use a special move
Complete a mission without using melee
Complete a mission without dying