Okies.
I'll start by saying that you are a fantastic animator. Your characters are exteremly well-drawn. The mouth animations are top-notch, and you have a knack for detail.
Unfortunately, your shining talent is bogged down by two things: your voices and your storyboard.
The voices suit the charcaters well, but I have a problem with Throwback's especially. His voice his quiet, choppy, and lacks emotion. It is a bit different for some of the others, but Throwback being the main character and all really hurts the movie with his voice.
Also, the storyboard lacks much. It simply did not keep me interested. I understand that this'll be a long series, but the lack in humor, when that is seemingly the main genre of this, bogs it down. You may be shooting for a more family-friendly animation here, but a few better jokes and gags would help.
Overall, this was a two-sided animation. While the quality of the animation and the characters were good, the flash fell under the weight of displeasing voice acting and a less-than-satisfactory story.
Keep up the animating, though!