Here is the full list of all 29 Longvinter achievements.
Get a kill
Kill 10 players
Kill 100 players
Craft an item
Get 5 000 in cash
Build a tent
Place 10 items
Equip a weapon
Go to snow region
Catch a fish
Get killed
Join a world for the first time
Build a fence
Plant a seed of wheat
Plant a berry
Unlock all fishes from compendium tab
Unlock all feathers from compendium tab
Unlock all plants from compendium tab
Kill a wild capercaillie
Cook food
Get 10 000 in cash
Get 20 000 in cash
Heal yourself to full health after your health drops down to 1
Have inventory filled with wood
Build a farming plot
Equip a hat
Place 50 items
Chop down 100 trees
Equip satellite communicator