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