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