Hi, Xosh project,
Thank you for your interest!
No, there’s no gravity. The package just contains a material that simulates visual effects of the atmosphere. It’s not intended to be a full-featured planet simulation. Sorry.
I can’t really answer your questions regarding LODs/polygons/landscapes because they are not part of this package. I suggest creating a separate thread and ask the community about that. I am sure that someone will help you. Sorry again.
Robert.