Hey, thanks!
Not sure what you mean by not totally round. Do you mean that the animation of the rotation is not complete, or that the shape of the planet itself is not round?
From what I can see from your image, the thin strip on the side can be caused if the spritesheet is spliced into the wrong number of sprites. So may you could try splicing it with a different amount of frames.
Let me know if that helps, if not, I'll try and fix whatever is wrong in the generator.