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