International Superstar Soccer 64 cheats and cheat codes for Nintendo 64

This game another title is J-League Perfect Striker.

Giant head players
Go to the title screen and press the following button combination:
C-Up, C-Up, C-Down, C-Down, C-Left, C-Right, C-Left, C-Right, B, A, 
hold Z + Start. If the code is accepted, you will hear the announcer to 
say "Goal".

Unlock Bonus teams
Go to the title screen and press the following button combination:
Up, L, Up, L, Down, L, Down, L, Left, R, Right, R, Left, R, Right, 
R, B, A, hold Z + Start.  If the code is accepted, you will hear 
the announcer to say "What an incredible comeback!". 
Go to the team selection screen and choose the "All Stars" option
to get access the six bonus teams. These are the followings:
African Stars, Asian Stars, Euro Stars A, Euro Stars B and 
All American Stars and World Stars teams.
or
Beat the game is league mode.