Select same boat
 
 At the track selection screen, select "Free Run" mode, then press
 Up(2), Down, Up, X.
 
 Extra mode
 
 Complete all the missions, finish in first place on all tracks, and
 collect all stone signs from the tracks. Then, the "????" selection
 on the options screen will turn into "Extra mode". Use this option to
 access a "Death Fight" feature and the bonus Marinoid Bay track.