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