Pac-Man World Rally - Unlock Nightmare Difficulty Setting

Unlock 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

Play as The Prince from Katamari Damacy:
Win the circuit races and rally under the easy difficulty setting.

Play as Pooka from Dig Dug:
Win the circuit races and rally under the normal difficulty setting.

Play as Fygar from Dig Dug:
Win the circuit races and rally under the hard difficulty setting.

Black Bomb:
Eat five blue ghosts in Pac-Mobile mode to unlock the Black Bomb upgrade for the Green Bomb.