I really hate this game. Problem is, there is absolutely not room for error on some of the levels. The solution is one click between two others on the circle. I'm not sure if that really makes sense, but when one is aiming, one can move the mouse so little that it "clicks." Anywho, I liked the music, it was relaxing.
the secret is to make combos as fast as you can. I prefer the big cluster bomb which is one turret and two missiles. Remember though, the turret must fire first.
 "StarShine"){kind=icon}
 "Onslaught2"){kind=icon}
 "Sexxes"){kind=icon}
 "Momentum Missile Mayhem"){kind=icon}