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