The idea of the game is that you need to factor a very large number which is a multiple of the first 8 primes: 2, 3, 5, 7, 11, 13, 17, and 19. So, for instance:

12355467391260000000 = 2^8 * 3^7 * 5^7 * 7^10

By pressing the left, right, up, down, A, B, X, and Y buttons, you can attempt to divide the large number by a prime. You can increase the power of the prime to attempt more points. Make a mistake and lose even more.

http://www.gp32x.com/board/index.php?showtopic=40775&view=findpost&p=588710