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