Here is the full list of all 12 One Manga Day achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Bad Ending I.
Bad Ending II.
Normal Ending.
Good Ending.
Be a true professional!
Pesky birds!
Can scan new pages for the team.
Can purify pages, make them clean.
Can translate some texts from language to language.
Can read and correct texts after translator.
Can type texts to the images.
Can find out prerelease shortcomings.