Here is the full list of all 16 School For The Friendless achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Get involved with the girls drawing on the board.
Went with Scout to the basement.
Punched Vivian's brother.
Get Anima as your roommate.
Get Scout as your roommate.
Get Vivian as your roommate.
Get Guy as your roommate.
Make Anima fall for you.
Be best friends with Anima at the end.
Get Anima's worst ending.
Make Scout fall for you.
Be best friends with Scout at the end.
Get Scout's worst ending.
Make Vivian fall for you.
Be best friends with Vivian at the end.
Get Vivian's worst ending.