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