I loved this game! It was a bit confusing to catch the light rays at first, but once I realised I have to predict the ray's position along the path of the same colour, I was able to figure it out. Had fun with the game, although I'd have preferred the controls for the Y-Axis were reversed.
Also, when it comes to giving the player objectives, maybe you should separate the colours immediately after they leave the prism? I don't know it made more sense to me because one second I was supposed to be going towards Earth and the next I was chasing after rays of light.
Amazing game, though.