The best part of the game, was perhaps not intended as a main feature. The musically inspired levels, which open up at the end of every subsection, are pure genius.
The level «Castle Rock», inspired by the song «Black Betty», is frequently replayed by me and my friends. The goal is to run and jump while avoiding any interruptions. You have to concentrate on the music, which hints at when you should jump, in order to make a perfect completion of the course.