I really really liked it!
Very nice artwork and animation, music was fitting. One thing though... the ninja completely destroyed those three guards, and then got killed by a measly gun... that's why I put 1 for humor because he died so craptastically. I liken his death to that of a death in Vampire Hunter D. When they're on the bridge, and that guy gets killed... I forget what happens exactly... I was a little tired when I watched, and it was over a year ago.. but he just dies so suddenly.
ANYWAY... great job! **spoilers** I love the end... my imagination, (along with most other people I assume), leads me to believe he shot himself but... who knows?? You say there's going to be more?? Well I personally can't wait!