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