The movie starts with a BANG! Literally! When you see the movie - you'll know why. (LOL). Yes its quite funny. The movie is kinda like Leon 'the professional' meets Kill Bill meets Kiss Kiss Bang Bang - for various aspects of the storyline - which may be inspired by nuances of these great movies.
The story line is a close parallel to that of Kill Bill's O'Ren Ishii sub-storyline i.e. her origins - as described by the Violent Anime that you see in Kill Bill Part 1. After you've been both movies, I'm sure you'll agree with my POV.
This is all out action. There is no sexual angle in my opinion unless you're a pedophile and get turned on by young looking early- teen/pre-teen girls. The movie has KungFu and MMA, it has guns, it has explosions and it even has some free running thrown in.
The twist (big reveal in the end) is fairly predictable - but that doesn't take away from the entertainment value of the movie. I'd probably watch this movie again, after some time.
The character development could use some work - but you're not expected to do anything but enjoy what you see - without any deep thinking or analysis - which is fine as well.
Watch this in the cinema or rent the Blu-Ray/DVD and enjoy pizza with friends. You're in for a blast!!