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