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