For Badge: Try to stay as close to the starting bubble as possible, killing the tiny blue bubbles first. By keeping central, you can get pretty buff, with little more effort and minimal bullet dodging you can max your ship. The final form is one big bullet, one small bullet and a force field. Once you hit this form, choose a dirrection and go that way, kill only the ships that shoot at you. When you need to refill your shield, go back and pick off the small ones for recharge. Keep a good shield and by the time you hit the boss, you should have little to no difficulty in defeating him. I hope this helps
For those looking to get the hard achievement, the one that requires 130 stars, you will notice there are 40 levels and each level grants 3 stars, which adds up to 120 stars. To get the extra 10... you're going to have to beat 10 levels without using all the shots to hit par.
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