Infilitrate the score rankings

First start a legue and after a game save the legue. Next when you can see the score rankings remember those players and press reset. Then go to the option mode trade screen and trade those players with anyone you want. Then press reset(not the one on the machine) and cancel that trade. Then goto the saved legue and check the score rankings. It should be changed.

Big Heads

At the title screen enter Top C, Top C, Bottom C, Bottom C, Left C, Right C, Left C, Right C, B, A, and then hold down Z and press Start.

Six Additional Teams

In the Japanesse version of ISS 64 (Perfect Striker), you get 2 additional teams by doing this trick, but in ISS 64, you get 6.

Using the D-Pad: Up, L, Up, L, Down, L, Down, L, Left, R, Right, R, Left, R, Right, R, B, A, and then hold down Z and press start.

If you did the code correctly, you'll hear the announcer say, "What an incredible comeback!" Then go to the Team Selection screen, and you'll see a seventh group of teams -- All Stars. This group includes Euro Stars A, Euro Stars B, Asian Stars, African Stars, All American Stars and World Stars.