Here is the full list of all 14 Journey achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Finish the game with the same partner for the majority of the journey and return to the beginning.
Meet 10 or more unique travelers.
Start the journey again after a week long break.
Reach the summit with a companion and return to the beginning.
Find a mysterious creature hidden in the temple.
Sneak through the underground passage without tearing your scarf.
Uncover all 10 ancient glyphs.
Collect all unique glowing symbols across one or more journeys.
Discover all cloth creatures in the desert.
Pass through 15 gates while surfing through the sunken city.
Find the hidden desert flower.
Cross the broken bridge without completely rebuilding it.
Sit and meditate with another player for more than 20 seconds.
Finish the game and return to the beginning.