Its pretty underrated and not really as poorly written as some think.

I will give up the point that there are some pacing issues, and characters could have been better developed. But its still a pretty good film, with really nice animation, especially the oni armour, and a pretty decent story that could have maybe been fleshed out some what.

But as far as plot holes and all this other nonsense, no. The main gripe I hear about is time travel. Here is the thing with that:

- the villians goal was to get Orochi, who controlled water; now what some of you may not graps is that water is the one thing that is essential to every living thing on this plant, even roaches and bacteria will die without water. Hence by controlling Orochi and water, he could basically have the whole world bow to him. So for him time travel was more a device or tool, not the means to an end

- as far as the oni, only the chief and his daughter appeared to have the ability, and even then it was highly limited requiring a cermony and seemingly only being able to send him back once, permanently

- on top of that, neither of those groups had full control over the ability, even the villian seemed to be limited to only forward travel plus a return trip; ie it did not seem he could pop anywhere he wanted, hence he could not go back in time to get an earlier member of the clan, etc.

Now on to some other points:

- most of the other issues simply need more background detail, which might have worked in a tv show, but even as it was the movie was 98 minutes

- I mean honestly go back and rewatch some of the Ghibli films and they have their weak points as well,even Spirited Away - I mean for all its hype (Its not close to Miyazaki's best) the last 10-20 minutes are muddy mess, from about the point where Sen gets on the train

Im not saying this movie is perfect, but it suffers more from being released too late, ie this movie would have fared better in the 1990s, then actually being a bad movie