I agree with what's been said thus far when it comes to the menu.
Even though I can see art not being a priority just yet, here are some tutorials that might make your main menu stand out a bit better:
Making Realistic Starfields
Making a Planet
I guess it depends on how detailed you want everything to be, though. I also think you could do with a better composition for your menu screen. Here are two of my suggestions:
- Making the planet larger and putting it in any corner of the screen would tighten up the menu a bit and frame it better. I'd say stick to the right side of the screen, mainly out of bias that it looks more aesthetically pleasing because many of us read left to right and it's easier on the eyes.
- Just looks a lot more epic and makes the screen feel potentially less cluttered.
Just my two cents on the menu itself, the other pieces of art are looking a lot better so I don't have much to say about them.
Good luck with your project.