It's a fun game. A few glitches lie here and there with the score resetting to a certain checkpoint sometimes and sometimes not, and the scoreboard doesn't open every time.
Also, is the dragon a cropped bitmap? If so, here's some advice to crop it better.
1) Make two layers, both with the dragon bitmap. Make one mask the other.
2) On the top layer, trace the bitmap with the default settings. After tracing the bitmap, the image will losing some detail, but that's fine since this layer will just be a mask.
3) Click on the white or background color and delete it.
4) Just the shape of the dragon will be the mask, and the color and details will show through from the layer below so long it's part of the masking.
5) Then just use the line or pencil tool to cut of the wings, as you already did here, and animate it, likewise, as you already did here.
If you're inexperienced with any of these functions of Flash, google them. It looks better like this in my opinion, since it removes most of the white, if not all. It's also great if you ever need to put your friends heads or something onto other things, but instead of just removing the background in that case, you'll need to remove anything but the head.