Here is the full list of all 22 Sword of Asumi achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Completed Death of Hikari Ending
Completed the 'canon' ending to the game
Saved the World and fell in love #1
Killed Utsuro at the End
Came first on the Obstacle Course
Get a perfect score in Tactics with Sen
Impress Kami with your poetry skills
Skipped the intro on second playthrough
Completed the Dying Alone Ending
Killed Mineko at the End
Completed Mercy is for the Weak Ending
Completed Hikari's Unrequited Love Ending
Saved the World and fell in love #4
Saved the World and fell in love #2
Completed the entire game at least once
Saved the World and fell in love #3
Assassinate the kidnappers after they talk
Try a little cosplay with Kaori
Drug the Principal for Information
Suggest to Kaori she is your type too
You Spread Rumours about Hiro & Jiro
Kill Everyone in the intro