Promising
Animation Style: looks like you put a lot of work into it. Though its hard to tell with such a small bit of the animation, but its looks good for the trailer/intro.
Characters: They all look rather interesting, yes they do look similar to other anime's, as well as games. But thats the style in its self, so I believe that it looks promising.
Backgrounds: Some look better then others, but each and everyone one has its own uniqueness, that makes it look good.
Music: Great choice, up beat ,and though it doesn't specifically go with the animation, the feeling it gives helps produce a better understanding of the show.
Improvement: Fluid animation is always a lot more time consuming, and work but if you can add more of it, the overall animation will look much better.
I'm no ace myself at drawing, though, I'm learning while animating as I assume you did in this. So if the end results of animation looks better then the start of you animation, you can always go back and edit the start.
Overall its looks great, and I hope you get better, and become one amazing artist.