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