awesome idea and nice ux - it's a bit too hard to gain credits since they very often overlap with an asteroid. But this looks like a fully developed game and you made it very easy to understand.
Thank you so much for your comment! By credits you mean the colored capsules? These aren't necessary for the score. You gain score points by every every meteor that is "eaten" by the black hole :D These capsules are power ups. They can give you extra points, health or delete all existing meteors from the screen.
But yes thank you so much for your feedback!!! <3