Nightmare Difficulty Setting -
To unlock the Nightmare difficulty setting, complete the Rally Cup on
Hard difficulty.
Cups -
Nore: Cups will only be unlocked for the difficulty at which you play
the required cups to unlock it. (i.e. beating the Watermelon Cup on
Normal will only get you the Classic Cup for Normal):
Classic Cup - Complete the Watermelon Cup
Rally Cup - Complete the Classic Cup
Watermelon Cup - Complete the Cherry and Grape Cups