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