Heaps and heaps of fun
Well done on making the game visually clear, i think many games like this have a problem of having too much clutter on screen to the point of which you lose track of your ship when looking ahead. You've managed to solve this problem really well as well as keeping the game visually appealing.
My only complaint is when you're using the mouse to control, and you have to get to the edge of the screen to avoid fire, it's very easy to have your mouse slip off and your ship become immobile. you could put a border around the screen where your mouse can go and still be in control of the ship, or make a fullscreen option.