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 Kruber
Reach level 30 with Kerillian
Equip a Veteran Item
Craft 50 items
Reach level 30 with Bardin
Reach level 30 with Saltzpyre
Unlock all Talent points for 1 career
Complete Skittergate on Legend
Equip Exotic items in every slot
Complete Skittergate on Champion
Complete a level as every Hero
Craft an Item
Salvage 100 items
Complete Skittergate on Veteran
Complete Skittergate on Recruit
Salvage an item
Equip an Exotic Item
Complete Act 2
Equip a Rare Item
Complete Act 3
Unlock 1st Talent point
Complete Act 1
Equip a Common Item
Complete Prologue