This is a really cool idea, very creative use of the art pack.
My biggest problem was dodging attacks. The ship moved really slow, I had to move my mouse really far to be able to dodge. Having the mouse go off screen wasn't a problem, the game ran in fullscreen so I was still able to move the ship and fire.
The first round I played, I was a little confused when I died. There was no indication that I was hit and I didn't know that my shield meter acted as my health. Maybe adding some sort of particle effect on the ship when it gets hit will help players know that you lost health, and if time allows it you can add another particle effect on the shield meter to indicate it went down. As other people mentioned, by the time I was done reading the instructions, I was already down to 1/4 of my shield, so maybe have a small grace period at the beginning.
Other than those small things, this is a really good first game. I like the little jingles and sound effects, and the space ship looks pretty cool. Definitely very creative and I would play more if it had more levels.