Howdy!
We did notice that walking (and jumping) close to the center of the planet is kind of disorienting. If you have any suggestions on how to make it less so (apart from making the planets larger), I'm all ears. We can't have a static camera either, as that would place the player upside down sometimes and invert the movement direction in a weird way.
The destructible terrain is my own implementation of the "marching squares" algorithm, so not a built-in unity component, sorry.