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