The rules of this minigame is to tap (with the stylus) either the yellow button (right) when the light shines on your character, or the purple button when the light doesn't shine on your character.
To me, this minigame was fun but I always beat the CPU's by 7 or 8. When I play with friends or experts, it's usually close. The remix of the Underground Theme from SMB was pretty catchy too.