Mitsurugi Kamui Hikae is what I like to call a "supplemental" game. This is a game you would play while taking a break from another similar "main" game. Some people would prefer to play a different game, but I don't know. Juggling a plethora of games that represent dozens of different genres would turn anybody's brain into stale yogurt. Why take the risk when you can play something similar that's stil entertaining?
This game - which I'll refer to as MKH because acronyms are fun (AAF) - falls under the genre of arena-slasher. Typically a character-action game has some mode where you fight wave after wave of enemies (Bloody Palace, Lost Chapter, Tests of Valor). When a character-action game is literally just that wave-based mode, it becomes an arena-slasher. These are pretty rare and tend to be doujin titles, like Croixleur Sigma (also available on Steam).
The plot to MKH is: woman kills stuff with katana. Each of the five chapters are divided into five waves. Enemies are rich in number but poor in identity. There are guys with swords, red guys with swords, yellow guys with swords, big guys with swords, robots, an evil schoolgirl, and maybe 1 or 2 other different types of enemies. However, this is a short game, one that you can slash through in less than two hours.
Not-evil schoolgirl (I already forgot her name) has a sweet sword and not much else when you start off. Upgrades can be purchased as well as new moves and powers. The #1 thing to keep in mind throughout is parrying. While it's easy to mash the attack button and slice evil to pieces, playing defensively is how you avoid getting your combos broken. More specifically, it's all about the parry. Blocking is fine, but it doesn't work on heavy attacks and tends to get broken by a continous assault. Timing the block just right allows NES to awesome her way through the enemy's attack and deliver a strong counter-move.
There are other tactics to keep in mind. When an enemy is struck enough times they'll start to bleed (turn red). At this point a few more hits are liable to kill the enemy, just before they die the player should sheathe their weapon. It's like that common Japanese maneuver where the samurai cuts a dozen people at once, but they only fall over and die after the sword's been sheathed. In this game it's just something you want to do to boost your skill-points & regain health, though it also does big damage to bosses. There are other abilities and skills to master, but it's better to get a feel for it while playing the game.
For the most part, MKH is a breezy entertaining slasher. It's satisfying getting those big combos while also deflecting numerous attacks coming from every angle. Keeping track of the action can be difficult though, and your sound has to be turned up to notice the enemies that inevitably attack from behind. Some more variety in the enemies and bosses would have been appreciated, but maybe it's just me. I've been playing Bayonetta 2 and it seems like every 10 minutes there's a new enemy to fight. Like I said though, MKH is a short game. 10 minutes in that game is at least 3 or 4 waves. New enemy-types would just get lost in the chaos.
Unlike the games it serves a supplementary role to, MKH can be enjoyed even if you only have 5 minutes of free-time. There's no sitting through cut-scenes or loading, nor does it take several minutes to get the action. It's also possible to save in-between waves, and you certainly aren't expected to play through the whole thing without dying. Start this game up, slash through a few waves, and put it down so you can focus on your main title.
All in all, this is a worthwhile pick-up.