Here is the full list of all 13 Lucid9: Inciting Incident achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Complete common route
Watch all the Gover Mecher episodes in one playthrough.
Watch none of the Gover Mecher episodes in one playthrough.
Get a 100% on your pop quiz.
Never select a wrong choice in the initial encounter with Shigure.
Never select or input a wrong answer for Shigure's puzzles.
Never select a wrong answer for the deduction sequence.
Pick the stall option as many times as you can without reaching a bad end.
Read all the investigation scenes at school.
Get all the bad endings with the murderer.
Have the option to choose to visit all available heroines.
Be unable to visit any heroine.
Select only the choices related to one heroine.