I love the overall atmosphere! I agree with others that it's amazing how you assemble assets from different sources and still give them a consistent style (usually it'll be a total mess for me!). Not only the sound and visual, but also how you set the speed and inertia parameters so that things float slowly in the space.
To be honest I didn't read your hint carefully and I headed to the most recognisable item, the planets. But I soon realised that I could only move them awkwardly. Maybe you'd want to attach more functionality on the planets, or leave them there as easter eggs?
P.S. I resonate with the problem of DoNotDestroyOnLoad. I really wish I know how to destroy some of them when I need :)