Hope this helps...
While your art isn't drop dead gorgeous, I really don't think you should knock it. It's quite good compared to a lot of art here on NG, and I for one think it's good enough to make a series on. If you want to improve though just try to take notice of small things from other professional artists (like comic book authors and such). Pick out what traits you like, and tweak your style to be something similar, but as I said, I think you're fine for the most part. Now, a few things. For starters, having someone's head completely explode (to the point that not even fragments of head remain) into a blood stain on the wall from a pistol blast is a bit much. That, and the way that the first cop didn't seem to worried by the fact that there was a gun to his face... Those things seemed a little unrealistic, know what I mean? I would like to know what direction you're gonna take this series in. There are a lot of options, but remember that if you want to make a series you're going to need a plot that can carry on for at least 3 episodes. I really look forward to what you're going to do with this series though. By the way, don't get discouraged if this preview gets a low score. About 99 out of 100 previews, trailers, and teasers get scores MUCH lower than the actual series will. I'll be watching out for this one. Good luck dude, God bless.