Stunt attack mode: Finish story mode to unlock this Tony Hawks style mode.
Unlock Characters:
Naomi: Get a grade B in the Downtown level
Insider: Get a grade B in the Downtown level
Oscar: Get a grade A on all levels
J.J. Saywer: Get a grade S on all levels
Costumes:
Ethan: Complete all levels in stunt attack
Kat: get the top 3 scores in scoreattack