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.
Explore all caves
Finish Game
Pass 50,000 steps
Cut down 1000 trees
Craft 10 medicine items
Find all missing passengers
Collect all robot pieces
In Single Player, don't kill any cannibals for more than 10 days in a row
Eat an entire family
Kill shark. Alone in Single Player or together in Multiplayer.
Build a super long wall
Revive 10 co-op players
Sleep with another player (group sleep)
Share a food or drink item in MP
Share a weapon in MP
Revive one co-op player
Kill all animal types and display heads
Catch fish with a trap. Alone in Single Player or together in Multiplayer.
Craft all items
Eat all mushroom types
Set off 20 bombs
Collect all cassette tapes!
Chop up 50 bodies
Kill 6 or more fish with a stick of dynamite. Alone in Single Player or together in Multiplayer.
Repair a shelter
Knock down 6 or more trees with 1 explosive. Alone in Single Player or together in Multiplayer.
Killed downed enemy with rock
Eat an enemy
Grow all plant types
In Single Player, kill 100 cannibals
Cut down 100 trees
Use the compass
Make and wear stealth armour
Sleep on yacht
Kill bird with arrow
Survive 5 nights
Kill a bunny. Alone in Single Player or together in Multiplayer.
Survive 1 night