There is very little effort made in setting up how or why the fight happened and so as a story the plot (i.e. the central conflict) is lacking. Man v. man, yes, but without setting it up there's no real story here. I'm happy I bought it and watched it as encouraging innovation in chambara or jidai geki (definitely the former). As entertainment it lacks because it goes on long enough to spot some glaring issues easily ignored in shorter scenes. 1) the shortest distance between two points is a line. From the middle stance, one is always threatening the throat strike as the most efficient killing blow but he never does it. I get it for safety's sake but after so much coverage it becomes more obvious. 2) no one who charges from the high stance has any actual intent to connect the downward swing. You can tell because he's easily able to connect a slice to the midriff (should be a "men" attack probably) before the downswing ever happens. He does this without needing to step forward or do anything to throw off their timing. 3) no coordination from the attackers. The very few times they attack simultaneously, it's high so both blows can be blocked with the same block. The only way they could have won would be such simultaneous attacks but from different angles & directions. I take issue with those who say no blood gets on his blade because it's manifestly inaccurate. I agree with those who say that the few extras in the exact same outfits & hairpieces is something easily perceived after so many minutes of coverage.
Things that still impress me 1) the actor's physical stamina. Even if the "sword" is light wood, it has to be heavy enough to receive a lot of blows without visually bending or distorting. The actor holds that thing up an impressive length of time. We used to do an exercise in my Okinawan style where we would hold our arms parallel to the ground for as long as we could and it was never long. We just couldn't do it. 2) the preparation of the character for the battle in advance. He knows he'll need extra swords & water, so he set them up in advance. I'd like to circle back to the actor's stamina here because until close to the end he drinks very little of the water, preferring to rinse his mouth & his "blade." He's obviously sweating for real & doing a lot off physical activity so again, impressive. 3) the fight scene at the end.
The last bit of criticism I have wasn't mentioned yet, and that is not letting us see the last opponent defeated. After making us sit through all that attacking without even giving us the emotional satisfaction of completion felt like a deliberate waste of our time. If they were going to cut away, why not edit? Why not show the ending after spending so much time setting it up.