Hello there.
I feel that everything seems timed. As far as i could see, the enemies projectile always travels in the same velocity and they never stop so i can kill then in safety. Or if the ideia is really this one, give more control on the ship, because it is more slower than the projectiles. The way is it right now, is frustrating.
And add screen shake, put impact in the actions. Make the people feel when i shoot and explosions happens.