When you have people whose skin is indestructible, or who can poke holes in walls with just their fingers, or who can run up walls and seemingly float or fly, would that be considered SciFi/Fantasy? (and, thus, appropriate for this forum?)
I was trying to connect and old-school Hong Kong movie to Kill Bill, over in the movie forum, but they seem to consider it a simple movie identification question and shot it down.
So, I am asking ahead of time, this time.
The answer is a qualified yes.
Obviously, there are martial arts that are completely mundane, such as those that are actually practiced in the real world. Some films make use of these, and they are not fantasy. For instance, The Karate Kid is just a sports movie in the style of Rocky, and nothing occurs that is flatly impossible in the real world.
However, in the type of cases that you mention, there are elements that are completely fantastical: super strength, super speed, flight, immortality and so forth. Since our site criteria are primarily based on plot elements, not on the vocabulary used to describe them, these certainly qualify, and they tend to be pervasive enough that the work is not just "realistic fiction where someone sees a ghost at the end."
In addition, these elements are likely intended as fantastical in most of these films, too: most real life martial artists do not claim that martial arts will grant the power of flight or immortality. So the writers' intention is usually to tell a cool story more than one that they think is actually a realistic portrayal of martial arts.
Obviously, in some cases, the dividing line is less clear. Some cases are more a mistaken understanding of human capabilities in what is intended to be a realistic story than someone actually trying to write a fantastic story. For instance, a martial artist might effortlessly fight off twelve trained soldiers at once, be able to break people's necks with their bare hands, and knock projectiles out of the air with their sword in pitched combat, all talents which would require essentially superhuman abilities in real life, but such a movie may not count because these are just common misunderstandings of what humans are capable of.
My own opinion, yes. Magical martial art moves, impossible in real world, are fantasy.
Kill Bill, specifically, has some SF elements, including a martial arts master who is several hundred years old. I think that is just about enough to make it valid for discussion on this SE.
