The game instantly thrust you into the action, which leaves you a little confused on what you're achieving.
You don't seem to have any control of the ship, other than it moving left or right.
There are only two types of enemies, and every other round is exactly the same.
I love how you try to incorporate music into the graphics, that's just wonderful, but it would be better if the music influenced more then just the background textures.
You also need to give firing control to the player. Letting the player of the game shoot as he/she chooses, and not having the game have a continuous, random fire.
Adding more than just two different enemies would be nice, hell, even adding more than just blue and green would be nice.
The game needs quite some work put into it, but if you try, it'll be a hit!