Cool and interesting experience, and definitely very tricky. It’s really appealing to watch the ever-changing gravities pulling each other around hierarchically. I managed to reach 300k mass by the end.
One visual idea: it could be cool to make the background stars more parallaxed, so the sense of depth and the effect of seeing the stars get smaller still works even when we get really big. Right now, at some point, they become a bit undefined.
Solid entry!