Has potential...
This does have some potential. Needs improvement in a few areas.
I know you said this is your first flash, but there are some things you should do if you want better reviews.
I know it's not about the reviews, but if you're making a series, then getting even one part blammed is bad for the whole.
The main thing here is to include audio. Music is good to include, but don't forget sound effects. Those two things will improve this quite a bit.
Also, the "action" was kind of bland. By action, I mean all that happens in the movie, not just fighting.
While audio can improve the quality, there are other things as well. Things like slowing down the slash at Zelda. That moment would do well to be slowed down, like in the Lord of the Rings: The Two Towers when the elf (NOT legolas or Elron) was about to be killed by Orcs.
I don't have flash, so I can't give you much advice about using it.
I can give you advice about presentation. Things like what kind of music to use, advice about improving scenes, etc.
For instance, the prologue would probably be helped by using a different background, because some words are a bit harder to read because the text does not work well with the background.
The background becomes green to display the text before the actual story part. It was kind of awkward having it change for just one bit of text. It's like having a TV show suddenly turn black for a brief instant when there is no reason to.
There are a few ways to handle that, however, besides a bland background. To help the prologue, use "cheerful" colors for text and background, but gradually darken them with each new text, or turn them into a different color at the end.
You could start with white text on a blue background, then gradually transition so that the final colors are red text on a black background.
Also, for the zombie, try to search the internet in case someone did a lower resolution ReDead. Someone on Newgrounds or elsewhere might make one, if you ask politely.
If you need advice about presentation, send me a PM. We can talk about stuff like that then.
The movie is good, but can be much better.
I hope you're not upset at my offer of help during a review. I thought that even if you didn't PM me, the examples I gave would be of help to you in the future.
I'm wondering how this will turn out. Keep on working on it, but try to make sure that the viewer won't be bored watching it.