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