Characters...
	Nightmare Difficulty...
	Tracks...
	Unlockable Weapons...

Fygar: You must complete Rally Cup on Hard Difficulty.
Pooka: You must complete 'Rally Cup' on Normal Difficulty.
The Prince: You must complete Rally Cup on Easy.

Complete every cup on Hard Mode with a gold trophy.

Easy Classic Cup: You must obtain a Gold Medal in Easy Watermelon Cup
Easy Rally Cup: You must obtain a Gold Medal in Easy Classic Cup
Easy Watermelon Cup: You must obtain a Gold Medal in Cherry Cup and Grapy Cup

To unlock more weapons/items you must collect a certain amount of ghosts (by eating other racers) in each cup.

Unlockable	How to Unlock
Black Bomb	Eat at least 5 ghosts in Cherry Cup
Galaga Ship.	Eat at least 12 ghosts in the Classic Cup.
Sir Pac-A-Lot.	Eat at least 10 ghosts in the Watermelon Cup.
Siria (Ice Dragon) Weapon.	Eat at least 8 ghosts in the Grape Cup.