Sengoku Musou is a historical fiction of japanese time period, Sengoku Jidai. This anime is based on a fighting game, and those animes have a negative stigma attached to them. This series shows that there is a very good reason.
When I watched this, I got a strange feeling that it was terrible. For some time, I was unable to really point out what was the reason, but then I realized. Remember that war sequence you saw in that action series you watched?
By war sequence, I mean that episode where someone narrates long-panning shots with still people with war sounds, strategic screens that show the army views and occassional hero fight. Though they at points are entairning, it is mostly because you have got to know some of the characters and you care about what they are going through, and that makes the war somewhat meaningful.
Now get the characters that you care about and remove them. The war sequence can still be pretty good, since it at least is used for meaningful world building. It is pretty easy to sit through a while of battles if it means you in the end understand more about the world of the series.
Now imagine 12 episodes of war sequence with no time to get to know any of the characters. Sounds fun?
There are some shows that are pretty monothonic, like Dragon Ball with all that saiyan fighting, Bleach with the sword stuff or Death Note with crime/mysery. This means that it is possible for a show to be about a single thing, so why doesn't Sengoku Musou work?
First of all, the characters are extremely flat. There's the gayish pacifist guy, the brutal strong guy, the calm glasses-guy, the elegant girl and the cute ninja girl with a freaking flying squirrel. The only times I got really interested for few moments about the characters were the 11th and last episode.
I haven't played the game this is based on, so I really can't tell if it's better or worse. What I can say is that this is bad.