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.
See the bad ending.
Clear the main game with the female protagonist
Save Kudoh.
Talk with Library multiple times.
Clear Truth with the male protagonist.
Free Kurata in the Truth route.
Give Misao some coins
Clear the main game with the male protagonist.
Find the message in the back of the laboratory.
Play the piano.
Jump off the rooftop.
Encounter Hanako.
Check your key items.
Get a whiff of a toilet.
Have a meal.
Hide in a cardboard box.
Refuse to help Yoshino.
Read "The Lazy-Eyed Ranger."
Read the diary in the library.
Make a quicksave.