I wondered why I was doing so well, and then I realized the other player was also me. :-)
It might be good to make certain reflection angles impossible on the top / bottom walls (or to ease them out). I got into a number of situations where there were fireballs bouncing at almost perpendicular angles, and all I could do was watch them slowly work their way over. Something to think about.
Otherwise, great little game and the art is definitely cool.