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.
Completed all endings.
Completed Michiko ending.
Chose to let Saori have Takeo to herself.
Completed Yuri ending.
Completed friendship ending.
Completed Takeo ending.
Took car to school.
Completed Keisuke ending.
Walked to school.