Split Down the Middle
One one side, it's nice if you have somebody over to play. Really, it is. On the other had, the graphics could use some work, and there should be a button that rotates the field. Most of all, the best improvement would be if you provided the SWF file. Then it could be hosted on a PSP, and you could take it around anywhere with anyone. Other than that, it needs one thing DESPERATELY. Make a rotation button.