It's a fun little prototype, but the size down doesn't really come across correctly - if I'm reading it right, it seems like you want to give a sense of scale (the center planetoid getting larger), but having the particles shrink without getting closer to the center ruins the "zoom out" effect it seems like you're going for.
Viewing post in A Game About Making A Planet - Prototype comments
it's kinda more of a practical solution to the player feedback seeing progress through play. I wanted the planet to grow but also be noticeable to the player. It has to grow quickly enough to be noticed. It also can't grow too large as if the play area gets small, the game gets too easy. So it's a way to show and reset progress for the player.