Boomerang Sports Tennis (Zeebo)
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"Godzilla" and "Little Player" Modes
On the last screen before the game starts (the one where you choose the duration of the match), hold your Boomerang joypad upside down, and enter these codes.
Code
Effect
Down, Press and Hold Down, 1
"Little Player" Mode (Little characters)
Up, Press and Hold Up, 1
"Godzilla" Mode (Giant characters)