I really enjoyed this since I love the games it's based on, and I wish I'd watched it sooner. However while I liked it a lot, I do see why someone who hasn't played the games or isn't familiar with the time period in general probably won't like it. There are lots of secondary characters and just not enough screen time for all of them, so if you don't know them and their stories beforehand you probably won't be able to feel as much for them as you can when you already know them. The show was probably made for fans of the game series,or at least that's the target audience for whom it works the best. If you have played the games or like sengoku-era in general I'd recommend this for you, but if you're just looking for some action with a historical setting, then this might not work for you.

Some short notions:

I liked how they used short map views and explanations during important battles because it gave the viewer a better idea about the whole picture: what was going on in the battlefield, what kind of tactics were used and so on. Ultimately this serves the story and characters since you know their story and what they are up to in the battle and how they are feeling during it.

They used the soundtrack from the games which was a good decision since it is a good soundtrack in my opinion, and at best brings additional feels for the fans of the series. The music has lots of energy and feeling to it, with both traditional and modern elements combined nicely.

The first couple episodes might feel a bit confusing if you're watching the show without experience of the games and/or time period, but the Sanada brothers story forms a coherent plot that takes us all the way from the beginning till the end.