Thanks for the thorough review & feedback! It's always nice to see people go out of their way to help someone improve.
As for the physics, it's a standard classical mechanics (newtonian physics) simulation. Basically, all objects (with mass) pull other objects with a certain force determined by the mass of the objects and the distance between them: F = (G * m1 * m2) / r^2. It was quite interesting to develop, seeing as it is pretty close to how gravity in our own Universe functions.
As for the level design issue, I totally agree. Solutions to levels should build on a breakthrough - learning something new about how the game functions - not pixel-perfect precision. It's sort of the same problem when you combine a platformer with a puzzler. It doesn't quite work out well.
On the topic of a tutorial, improved difficulty scaling and polish, these are definitely things that could turn this, as it is now, experimental project into a game. I definitely want to continue building off this project, and give thought to how to turn this physics simulation into a game.
I'm glad you liked the idea, and it's very inspiring to hear that you think there's great potential. Thanks again!