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.
Catch fish with a trap. Alone in Single Player or together in Multiplayer.
In Single Player, kill 100 cannibals
Kill shark. Alone in Single Player or together in Multiplayer.
Kill a bunny. Alone in Single Player or together in Multiplayer.
Play through entire game without killing or eating animals. Alone in Single Player or together in Multiplayer.
Killed downed enemy with rock
Craft all items
Craft 10 medicine items
Build a super long wall
Pass 50,000 steps
Kill all animal types and display heads
Find all missing passengers
Cut down 1000 trees
Explore all caves
Eat all mushroom types
Set off 20 bombs
Grow all plant types
Collect all cassette tapes!
Kill bird with arrow
Repair a shelter
Knock down 6 or more trees with 1 explosive. Alone in Single Player or together in Multiplayer.
Sleep on yacht
Finish Game
Revive 10 co-op players
Collect all robot pieces
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
Chop up 50 bodies
Eat an entire family
Make and wear stealth armour
Survive 5 nights
Cut down 100 trees
Share a weapon in MP
Share a food or drink item in MP
Eat an enemy
Use the compass
Sleep with another player (group sleep)
Revive one co-op player
Survive 1 night