Here is the full list of all 29 Longvinter achievements.
Build a fence
Craft an item
Equip a hat
Build a tent
Equip a weapon
Get killed
Cook food
Catch a fish
Go to snow region
Place 10 items
Join a world for the first time
Get a kill
Kill 10 players
Kill 100 players
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
Get 5 000 in cash
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
Place 50 items
Chop down 100 trees
Equip satellite communicator