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.
Revive 10 co-op players
Cut down 1000 trees
Eat all mushroom types
Kill all animal types and display heads
Play through entire game without killing or eating animals. Alone in Single Player or together in Multiplayer.
In Single Player, don't kill any cannibals for more than 10 days in a row
Explore all caves
Finish Game
Find all missing passengers
Collect all cassette tapes!
Collect all robot pieces
Revive one co-op player
Share a food or drink item in MP
Share a weapon in MP
Build a super long wall
Craft 10 medicine items
Craft all items
Pass 50,000 steps
Grow all plant types
Kill shark. Alone in Single Player or together in Multiplayer.
Catch fish with a trap. Alone in Single Player or together in Multiplayer.
Eat an entire family
Chop up 50 bodies
Set off 20 bombs
Repair a shelter
Eat an enemy
Sleep with another player (group sleep)
Kill 6 or more fish with a stick of dynamite. Alone in Single Player or together in Multiplayer.
In Single Player, kill 100 cannibals
Knock down 6 or more trees with 1 explosive. Alone in Single Player or together in Multiplayer.
Kill a bunny. Alone in Single Player or together in Multiplayer.
Make and wear stealth armour
Kill bird with arrow
Killed downed enemy with rock
Cut down 100 trees
Survive 5 nights
Use the compass
Sleep on yacht
Survive 1 night