I've played this a couple of times, I got to level 4, and it's not bad.
The graphics are really good and I like that I can play it with my gamepad. I like the exploding asteroids.
The menus were good but I didn't like the way the cursor would jump back to its starting position in each sub-menu.
I found the game became repetitive very quickly. It would be nice if they was more variety of enemy, level design and weapons.
Maybe have some larger ships or a large space station. It doesn't necessarily have to be interactive or something the player fights but just use it as a peace of scenery (a bit like flying through the Death Star in Return of the Jedi).
It would be nice if the space fighter could roll. I understand why it moves the way it does but it doesn't feel quite right.
Overall, I think this is a good effort, it's obvious that you've put a lot of work into it.
Just out of interest, why didn't you do a WIP post? I think you might find it helpful to get some input during the development.