Here is the full list of all 9 Mermaid Mission: Titanic achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
For picking a really stupid alias
Got all achievements
Unlocked all three endings
For solving all the puzzles.
For escaping the bulkheads
For sorting all the groceries
For navigating the shark caves
For getting kidnapped
For making it to the human world