Here is the full list of all 45 The Forest achievements. It takes around 50-60 hours to unlock all of the achievements on Windows.
Play through entire game without killing or eating animals. Alone in Single Player or together in Multiplayer.
Finish Game
Pass 50,000 steps
Cut down 1000 trees
Build a super long wall
Explore all caves
Kill shark. Alone in Single Player or together in Multiplayer.
Eat all mushroom types
In Single Player, kill 100 cannibals
Kill a bunny. Alone in Single Player or together in Multiplayer.
Catch fish with a trap. Alone in Single Player or together in Multiplayer.
Set off 20 bombs
Killed downed enemy with rock
Craft all items
Repair a shelter
Revive 10 co-op players
Revive one co-op player
Collect all robot pieces
Find all missing passengers
Grow all plant types
Knock down 6 or more trees with 1 explosive. Alone in Single Player or together in Multiplayer.
Kill 6 or more fish with a stick of dynamite. Alone in Single Player or together in Multiplayer.
Craft 10 medicine items
Kill all animal types and display heads
Eat an entire family
Use the compass
Collect all cassette tapes!
In Single Player, don't kill any cannibals for more than 10 days in a row
Cut down 100 trees
Chop up 50 bodies
Sleep on yacht
Eat an enemy
Make and wear stealth armour
Share a food or drink item in MP
Kill bird with arrow
Share a weapon in MP
Survive 5 nights
Survive 1 night
Sleep with another player (group sleep)