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