Unlock Hidden Characters
In several of the Ghost Zone stages there are hidden characters which you can get to if you have Grannie. When you have rescued these characters and cleared the stage you will be able to pick them from the 'Character' select menu at the 'Title' screen. These hidden characters will ALL play the same as Grannie).
Ghost Zone 1-1 Hidden Character:
Boost straight up from the start to find him.
Ghost Zone 2-1 Hidden Character:
Boost above the first Checkpoint to find him.
Ghost Zone 3-1 Hidden Character:
Boost upwards as soon as you are out of the narrow path.
Ghost Zone 4-4 Hidden Character:
Boost upwards at the start to find him.