Here is the full list of all 26 Warhammer: Vermintide 2 achievements. It takes around 120-150 hours to unlock all of the achievements on Windows.
Reach level 30 with Sienna
Reach Level 30 with all characters
Reach level 30 with Bardin
Reach level 30 with Saltzpyre
Complete a level as every Hero
Complete Skittergate on Veteran
Complete Skittergate on Champion
Complete Skittergate on Legend
Equip a Veteran Item
Complete Prologue
Complete Skittergate on Recruit
Complete Act 1
Complete Act 3
Complete Act 2
Salvage 100 items
Salvage an item
Equip a Rare Item
Equip a Common Item
Equip an Exotic Item
Equip Exotic items in every slot
Reach level 30 with Kruber
Unlock 1st Talent point
Unlock all Talent points for 1 career
Craft an Item
Craft 50 items
Reach level 30 with Kerillian