Here is the full list of all 41 Warhammer 40,000: Shootas, Blood & Teef achievements.
Completed all levels on hard
Killed 20 Commisars
Meleed an ally 100 times
Defeated Warlord Gutrekka
Defeated the Killakan
Killed 500 Orks
Consumed 200 squigs
Defeated Lord Horrik Canorem, Son of High King Valorik Canorem, High Prince of House Canorem, Master of the Blade of Gaia, Keeper of the Gates of Loralo, Wielder of the Kaloric Flame, Bringer of Hope, Herald of the Holy Order of the Adamantine Lance, The Paladin of Koto, Slayer of the Lion of Essa, The Triumphant! The Light of Stars! The Eradicator!
Defeated the invictor warsuit
Used Storm Dash to bash enemies 200 times
Killed 75 Tempestus Scions
Bought every weapon in the store
Killed 200 enemies by throwing the Beast Snagga spear.
Killed 500 Astra Militarum
Entered WAAAGH! 100 times
Defeated the Chaplain
Killed 1 Space Marine
Killed 5 Tempestus Scions
Defeated the Sentinel
Defeated the Genestealer Duo
Didn't consume ammo 1000 times as Flash Git
Defeated The Patriarch
Defeated the Biophagus
Defeated the genestealer
Killed 10 Genestealer Cultists
Killed 10 sewer enemies
Defeated The Bastion of Valor
Killed 100 enemies with melee attacks
Shocked 200 enemies as the Weird Boy
Defeated the Leman Russ
Killed 1 Commisar
Defeated the Boss Nob
Killed 10 Astra Militarum
Killed 10 Orks
Killed 100 enemies with grenades
Found all secrets hidden troughout the game
Killed 25 Space Marines
Killed 500 sewer enemies
Killed 500 Genestealer Cultist
Bought every hat in the store
Completed all other achievements