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 getting kidnapped
For solving all the puzzles.
For sorting all the groceries
For escaping the bulkheads
For making it to the human world
For navigating the shark caves