After watching the original movie and falling in absolute love with it I learned of the TV series. I was so ecstatic to watch what I thought would be an incredible series, to say I was dissapointed would be an understatement.
Story: This isn't where this anime fails. In fact I don't even mind the story, it's interesting but not incredibly original. Everyone wants to kill Shigure and there's only Jubei and two minor characters to protect her. Storyline progression isn't that great, I found myself in the 5th episode going "is something going to happen?"
Animation: Watching this anime didn't make my eyes carefully try to understand what I was seeing. Sometimes when I'm watching an anime (mainly Gankutsuou) I read the subtitles as quickly as possible so i can appreciate the art. Not so here.
Sound/Music: Honestly, when it comes to anime I believe that music is one of those subtle things that makes a great anime even greater, or a terrible anime much worse. Or whichever combination you like. I actually enjoyed the music in this, it did suit the feel of this anime.
Characters: Here is where this anime fails miserably. For people who have seen the movie you'll definitely recognize the monk and Jubei. The other characters are all new. The characters are all one-dimensional. I never found myself rooting for any character because the outcome, I knew, was going to be the same. All enemy ninjas bored me, every single one of them. I'm not a huge fan of monsters in a ninja series, i like them to be more human. I mean sure, throw in a couple monsters, but....when every character except the main party are monsters...it gets really boring. And they're all the stereotypes. I felt all the characters to be very Trigun-ish and when i looked it up, the character designer for Ninja Scroll was also the designer for Trigun. It worked for Trigun, it doesn't work for Ninja Scroll.
Enjoyment: I almost didn't want to finish this series. 13 episodes long, a little over 4 hours and i didn't want to finish it. I chuckled a few times, was entertained for a little bit each episode. But not nearly enough for me to actually have a good opinion of it.
Overall: A series which, compared to the film it was based off of, is horrible. If you haven't seen the movie you might disagree "I think your opinion is terrible, I quite enjoyed this series." I came in expecting to see something that would satisfy me the same way the movie did, and it didn't. I would however, recommend this if you're just needing some ninja-action.