Just saw it this afternoon. As far as the volume of blood shown is concerned, it is a pretty safe bet that few or no films in recent history have the sheer amount spilled, splashed, projected and gushed as in this film. Also the number of 'displaced' limbs is significant, which of course occurs when alot of people swing around sharp objects. Overall a 10/10 amount for gore, but qualified as mostly blood, a fair amount of body parts, and few internal organs.
But regarding the gore, it could be considered cartoonishly realistic. That is to say that it is done in such a visual style that much of it is more similar to samurai action anime than say live action movies like Starship Troopers, Braveheart or Saving Private Ryan. The offbeat soundtrack throughout much of the film and during the fight scenes also affects the context of the visual effects.
Basically the way it was filmed makes it pretty subjective as to whether or not someone would consider the gore just gratuitous, or 'appropriate' in the context of the story. Also not wanting to spoil too much, but there are many different cinematic styles that are used throughout the film.
But despite all the red stuff I'd still recommend this film and will definately be seeing Volume 2.