The New Tetris

For a real challenge, select single player mode, enter 2FAST4U as a name, then highlight "OK" and press A.
When the game begins, the blocks will eventually fall very quickly.
To give your CPU opponent a boost, select single player mode, enter AI2EZ4U? as a name, then highlight "OK" and press A.
When the game begins, the CPU's blocks will fall very quickly, while your blocks will remain at normal speed.

To see a musical kaleidoscope, enter the audio options screen, set the song to "Haluci" and the music mode to "Choose". Then select single player mode, enter HALUCI as a name, highlight "OK", and press A.
A kaleidoscope will appear in place of the game.

Note: The Nintendo 64 must be reset to quit this mode.