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