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