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