Rap "Cool"
To be able to rap "Cool" first you must complete all the levels in story mode. Be sure to save the game.Using the current saved game,try level one for starters. To rap cool,add your own flair by pressing the buttons more than needed and/or doing the button pattern multiple times. Your rating will go up to to flashing Cool, achieve this several times and the lead character of the level will stop rapping and let you "Freestyle" by youself. Try to keep good flows otherwise you may lose the cool rating.
Better Level endings
Finish every level with a Cool rating and the end sequences will be even better for Parappa.
Unlock "Sunny and the Funshine Band"
Complete every level with a cool rating. You'll have a a new level to select. Sunny Funny and Katy Kat dance on a table and you can change there clothes, and change camera angles