Here is the full list of all 18 Message Quest achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Merge roads for the first time.
Find the second princess.
Take the scroll.
Sit on the Responsibility Stool.
Find the first princess.
Survive the Innkeeper's attack.
Everyone needs to try it.
Tell a story that nobody's heard before.
Persuade the King of Bards.
Defeat Laziness.
Become a true hero.
Save the refugees.
Make yourself useful.
Get all the answers.
Restore the banner.
Put together the scroll.
Meet with Yorick.
Resist temptation.