This game is really addictive, i can't stop playin' it, but there are some things I have to criticise.
At first the Paratroopers are good to kill other flying objescts, but make it nearly impossible to get the full amount of stars. Another Problem is the Animation of the bonus stars(the ones you have to collide with), sometimes the stars get hit and start to animate that they've been hit, but suddenly the level is over, because all units are dead.
If you would fix this you'll get a 5 star rating.
However good game, keep up the good work.
Hope u will be able to fix the problems.