Here is the full list of all 21 Misao: Definitive Edition achievements. It takes around 4-5 hours to unlock all of the achievements on Windows.
Clear Truth with the female protagonist.
Clear the main game with the female protagonist
Talk with Library multiple times.
Clear Truth with the male protagonist.
Free Kurata in the Truth route.
Give Misao some coins
See the bad ending.
Clear the main game with the male protagonist.
Read the diary in the library.
Find the message in the back of the laboratory.
Play the piano.
Encounter Hanako.
Save Kudoh.
Hide in a cardboard box.
Refuse to help Yoshino.
Have a meal.
Get a whiff of a toilet.
Jump off the rooftop.
Read "The Lazy-Eyed Ranger."
Check your key items.
Make a quicksave.