Here is the full list of all 33 Mitsurugi Kamui Hikae achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Clear Easy difficulty
Defeat stage 5 boss "Magatsu Suzuka" (any difficulty)
Defeat stage 6 boss "Magatsu Hino Tsurugi" (any difficulty)
Perform 10 Just Guards
Max out Life Gauge
Defeat stage 1 boss "Kaina" (any difficulty)
Defeat stage 2 boss "Kaiser" (any difficulty)
Defeat stage 3 boss "Suzuka" (any difficulty)
Defeat stage 4 boss "Magatsu Kaina" (any difficulty)
Defeat 10 enemies
Defeat 100 enemies
Use Zanshin to defeat an enemy
Use Zanshin to defeat 50 enemies
Use Zanshin to defeat 100 enemies
String 50 hits
String 100 hits
Perform the holy technique "Celestial Judgement"
Perform a Just Guard
Reach "Mitsurugi" zeal level
Watch the tutorial
Clear Normal difficulty
Clear Hard difficulty
Clear Very Hard difficulty
Defeat 1000 enemies
Perform the holy technique "Divine Wind"
Perform a Counter
Perform 10 Counters
Perform a Flourish
Perform 10 Flourishes
Complete all upgrades
Collect 100,000 SP
Max out Katana Gauge
Clear Inferno difficulty