Here is the full list of all 21 Jusant achievements. It takes around 5-6 hours to unlock all of the achievements on Windows.
Place a piton at the top of a wall run.
Complete the game.
Use the echo on a frozen ballast in Chapter 6.
Warm up the ballast in chapter 6.
Complete all cairns.
Listen to all shells.
Turn all altars.
Activate all frescos.
Read all of Bianca's journal entries.
Read all letters.
Complete more than 200 jumps or double jumps in one game.
Restore your stamina more than 50 times while climbing.
Stop 25 pebbles with a single echo from the ballast.
Hug the ballast 20 times.
Turn an altar.
Hug the ballast.
Activate a fresco.
Scare more than 10 chocos back to their burrow.
Complete a cairn.
Listen to a shell.
Read a letter.