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