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