Try using the scenes to the right, the most to the right is the best scene including the highest number of planets and high LOD resolutions and smaller gaps between meshes, but your computer should be powerful, you can try it if you want and check if your computer can handle it.
There are a lot of keys for controlling the spaceship: left right up down arrows, U J H K, A, W, S, D, I, F. in the game page there is a full description of how to use any one of the keys, I know the game should show you how to use everything as a good game design, but this was made as a project and focused on making the generation and the optimizations that the player don't see.
with all that being said, thank you very much for your feedback