Nice Job! Great anime opening, especially if you don't quite have a firm grasp on Flash yet. The only big thing that bothered me was the art style, but I totally bought into it when hair started blowing at six seconds. At that point I said out loud "Nice. Okay, I can deal with it."
A couple of small things:
First, when the three large stripes of colors come with the flashing portraits, I think it would be better if the portraits get a little more screen time. Since they are all white outlines it's hard to tell them apart, and they come and go so fast that by the last time it happened I didn't even try to see the faces.
Second, the gun shot to the head. I don't know why it bothered me, but I felt like you were blowing your load prematurely so to speak. It would be like if the opening to the first episode of Trigun showed Vash with his giant gun arm shooting the moon. Maybe have her fire and have the guy watching the bullet come towards his head, bullet time style, and then cut right before it hits? Maybe I'm crazy...
Anyway, I enjoyed it and am looking forward to actual episodes.!