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