Honestly, it's really bad. First of all, let's not fool ourselves with euphemisms about the animation, such as "unique." Its trashy CG that wasn't even good on release, barring talking about being compared to today's standards. Not to mention, fights are nonexistent, due to the low budget, I'd assume. Very off putting. But I was willing to give it a shot because maybe the other areas can compensate. Not the case, unfortunately.
The characters are terrible. For such a unique story/plot, you'd think that the characters would at least be half decent. Wrong. All of Nobunaga's aids are trashy. They basically all blindly follow him. Even the characters very close to Nobunaga, there is no form of trust being built, but rather, just an acceptance after an episode or two. The characters are a mere foil to our protagonist, and when it is convenient for plot and character progression, they kill themselves off to serve as motivation. In reality, none of the characters are unique, and merely act off a script that was made to progress the plot.
The story, is actually super cool. Impersonating a famous historical figure, with only a textbook to go off of, it is a start of a very successful storyline. Unfortunately, the characters are very offputting, and the protagonist is nonsensical. I get that the protagonist is supposed to be lazy high schooler, but he's actually just stupid. But hey, since he is the main character, everything he does is obviously going to work out! Plot armor logic.
Rather than call this a hidden gem, it's more of a well deserved forgotten anime. With a solid foundation, but without any sort of "oomph" to get it running, whether that be the art, characters, or the storyline progression, it indeed is quite bad.
