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