The idea of slinging the bullets back is super cool, the most fun I had was collecting a bunch of them and smashing something in one shot.
I died a number of times thinking I was just collecting a bullet, it would be cool to have an indicator showing how close they needed to be to be caught. Or maybe have them just shoot alternate bullets that you could catch.
I suck at these games though so maybe other people wouldn't have as much trouble, story was fun too, Pluto getting it's revenge.