Here is the full list of all 14 Submerged: Hidden Depths achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Collect all Diaries
Collect all Boat Boosts
Collect all Creatures
Visit all Landmarks
Collect all Relics
Finish the Campaign
Collect all Styles
Collect all Flowers
Use all Lookouts
Change Body Style
View a Relic at the Home Base
Change Hair Style
Change Boat Style
Put a Flower in your hair