Not being familiar with the games, Sengoku Basara was a look into the unknown, despite hearing the name a few times from a number of people, and most of them loved it. Going through it, I can definitely agree about the series being a goodie, but just fails to break into really good.
The first episode is your typical introduction to the main characters and the plot '" though it does it in style, as we get a battle sequence in widescreen magic between the two main characters, Date Masamune, the young cocky warlord of the Date clan, a cocky eye patch wearing samurai who has the ability and skill to fight using 6 swords at a time. His counterpart, Sanada Yukimura, loyal to his master Shingen, a fire based warrior who is a happy go lucky guy who is a main source of the comic moments in the series '" and are quickly established as the rival to each other.
Based on real life characters of the Sengoku period, the series is essentially about several warlords trying to rule over each other. Yukimura's mentor and master, Takeda Shingen '" has a rivalry in respectful terms with the handsome Useugi Kenshin '" along with them they have their own bodyguards, Sasuke - a ninja with a sense of humour who enjoy teasing Kenshin's bodyguard, a female ninja named Kasuga who is implied to say the least to be Kenshin's lover. From there alone, we get split into several other mini arcs with other countries being ruled and ready to be taken over. However, things change when the arrival of the Demon King, Oda Nobunga arrives on the scene. He has some ability to control and use darkness to a degree that his nickname is more to his seemingly godly power, scaring all the countries and to do his bidding '" as in the second episode, his appearance along with his followers take out a cowardly ruler.
Other characters are introduced as an unholy alliance to defend themselves against the Demon King is formed. The main problem hits us quickly in these first few episodes, as there are simply too many characters for a 13 episode series to really flesh them out. For example episode 3 introduces what seems to be a comic relief character named Keiji, who is the main reason that the alliance eventually gets formed. However, despite being the focus for the entire episode, soon after his fight with Masamune, he's barely mentioned or shown much throughout the remainder of the series. Episode 4 again introduces a character that could be interesting named Nagamasa, who is the brother-of-law of Nobunga, and his wife (and Nobunga's sister) Oichi. However, a couple of episodes later, and his brief moments in the spotlight are abruptly cut off.