Here is the full list of all 9 Last Days of Spring Visual Novel achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Took car to school.
Completed all endings.
Completed Yuri ending.
Completed friendship ending.
Chose to let Saori have Takeo to herself.
Completed Takeo ending.
Completed Keisuke ending.
Completed Michiko ending.
Walked to school.