Actually not that far away. According to the idea, it was supposed to be a space combat simulator with N-body physics, where each celestial body, in proportion to its mass and distance from others, affected the rest, including the player's ship itself.
But I ran into a misunderstanding of how to implement the prediction of the movement of the player's ship, let alone other features. In fact, all that was ready was the gravity system (the celestial bodies were not nailed to the routes of movement, their speed was set in the initial configuration and could change) the ship and a simple control system for it by giving it acceleration along its relative axes, including rotation and a little bit of textures.
As for your game, if you manage to add multiplayer to your project, it will be an EXTREMELY serious bid for the success of the game, perhaps even financially, all that I know of on the market is literally either games that do not have weapons (KSP), or no orbits (Space Engineers), or no multiplayer (Children of the Dead Earth).
Adding multiplayer will set this game apart from others, all that's needed next is to add more presentable graphics, easy-to-implement but entertaining game modes, and you have a project ready that will attract a fairly wide niche of players, and the game itself will not have competitors in the market.