Gun Woman is currently available on Netflix.
From IMDB: A brilliant doctor on a quest for revenge buys a young woman and trains her to be the ultimate assassin, implanting gun parts in her body that she must later assemble and use to kill her target before she bleeds to death.
Directed and written by Kurando Mitsutake
Starring: Asami, Kairi Narita, Noriaki Kamata, Matthew Floyd Miller, Dean Simone
TL;DR Pretty good movie. A very disturbing villain – someone you want to see get theirs. Copious amounts of nudity – just not the good kind.
Trick or Treat Radio podcast #188 features an interview with Kurando Mitsutake. They reviewed the movie itself in episode #153.