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