Here's a quick way to see player data:

• First League: Press C-Up (x2), C-Down (x2), C-Left, C-Right, C-Left, C-Right, Start at the status screen.
• Second League: Press C-Up (x2), C-Down (x2), C-Up, C-Down, C-Up, C-Down, Start at the status screen.

Press C-Up, C-Left, C-Right, C-Up, C-Right (x2), Z, C-Left, C-Right, C-Left, C-Right, Start at the stadium selection screen to unlock each and ever stadium in the game.

Switch the game/N64 own with your controller plugged into the second controller port only. Then enter the following code to erase all user data: Up, C-Up, Down, C-Down, Left, C-Right, Left, C-Right, Start.