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