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