I liked Death Proof, but I'm a weirdo.
I just watched Blade Of The Immortal:
It is based on my favorite comic book series. Obviously you're not gonna fit all of the 30+ volume run of a comic series into a movie without cutting out a pretty huge chunk of it and glossing over even more, but I was actually sorta shocked at just how much they kept in the film. Honestly, I think this is about as good an adaptation of the books series as you could ever hope to make, given a single film. They cut out basically the entire second half of the series and end it VERY differently from the book as a result, but it's actually kinda shocking how much they got in there. If it has been done as a 2-part series and gone over more of the weird espionage / politics stuff and slowed down a bit while including more of the plot (including some of the bigger 'third-act' sequences from the book that would have happened after this film's plot) I think it could have been a resounding success.
As it is, tho, I would still recommend it. The plot in this version is more or less a Cliff's Notes version, with a TON of plot elements, characters and character beats totally missing, but it's an ace flick if you like feudal japanese sword flicks. If you've ever thought "man, this movie had an awesome sword fight at the beginning and the end and then the middle got kinda overly boring", then this is your flick. There are awesome sword fights every ten minutes.
The one big disappointment I have is that they misplaced the villain. In the books there are multiple villains that swap out during the series. It starts out much like it is in the film, but somewhere in the middle you realize that Anotsu isn't actually a villain, that Rin and Manji aren't really good guys, and there's a lot more gray area than you realized. And then Shira gets even more fucked up and there's a sub-plot with a kid that Rin bumps into, and then there's the political intrigue that this film sorta crams into the second half in a sorta non-subtle way...
At some point you realize that there's not a protagonist or an antagonist, but that they're all protagonists and they're all antagonists, and it just depends on whose point of view you're seeing things through. The characters themselves don't even seem to know where they stand with each other by the end of the series. That's the sort of stuff that's really hard to cram into a movie, tho, when you have to have things like sword fights and plot lines.
Bottom line is that I liked it a lot more than I was expecting, and they crammed a lot more into it than I was expecting, and Miike had the common sense to not rush the pacing the whole time. There are scenes and shots that linger, and there are some nice character beats and moments that I think most US studios would probably have cut out to keep the running time down. I very much recommend it if you like action and don't mind the weird cheesiness that Japanese schlock can sometimes have.