Could be really good.
There is plenty of back story to explain as well as who the hell Joshua is and who he is working for so in the story department you are pretty set. I would, however, study up on stick animation and try to get a smoother animation style so that the action isn't quite so block. Also, do not make the music the focus, get a couple of buddies to help you with voice acting and make the music background. These are my ideas as to what can make this very mediocre flash into an awesome series.