Nice little game! Everything worked really well and it was immediately clear what to do. For my liking it could have been a bit harder, but that is probably just my taste in games :P
I found myself trying to get those yellow stars, even if I was at full health. Maybe it would have been nice if those added to your score somehow? Another point of feedback is that it was not very clear to me how much health I had left. I see now in the other comments that I could have looked at the power engine, but still something to think about!
Thanks for making this! I enjoyed playing it :D