Get a bronze or better on the Rare
Complete story mode on the normal or hard difficulty
Complete the Amateur League with golds
Complete the Behind The Undead challenge with a medal
Complete the Cats Out Of The Bag challenge with a medal
You can play some music in arcade mode... Firstly you need to pick a game type... Any one will do except for mapmaking. Then select Disco and a character. Then move over to the instruments and press some buttons.
Added by: Team SuperCheats Jun 15th 2006, ID#5854