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