NBA Courtside 2: Featuring Kobe Bryant

Cheat mode:
Press C-Up + C-Down at the main menu to display the cheat screen.
The message "You have found the secret room. Press some buttons and see what happens" will appear to confirm correct code entry.

Small players
Press C-Up, C-Down at the cheat screen.

Big heads
Press C-Up(2), C-Down at the cheat screen.

Long necks
Press C-Up(2), C-Down, C-Up, C-Down at the cheat screen.

Bonus teams
Press C-Up(2), C-Down(2), C-Up(2), C-Down(2) at the cheat screen.

Big heads for home team
Press C-Up(2), C-Down at the cheat screen.

Big heads for away team
Press C-Up(2), C-Down, C-Left, C-Right at the cheat screen.

Big heads for both teams
Press C-Up(2), C-Down, C-Right, C-Down at the cheat screen.
(Information from Cheat Machine)