The music was very nice! Did you make it yourself? The mechanics were cool, too. The jumping had a nice feel to it, though it seemed a little inconsistent. Not sure what the purpose and logic behind shrinking and growing was, I thought it might have something to do with the planets' sizes, but doesn't seem to be the case. The jumping felt a little inconsistent, sometimes I ended up inside a planet and it would restart a few seconds after. If that was intended, it wasn't clear. I got to the end by going around "the sun" and landed on a gray planet/moon after that. In the end - very short, but pretty fun!
Oh btw, in the instructions it said to move with arrow keys, but I could only control the character with WASD.