Unlock the following characters by performing the corresponding tasks:
CHARACTER - HOW TO UNLOCK
Cube/Combo - Complete Chapter 1
Play as Garam - To unlock Garam simply complete his challenges.
Play as Goji - To play as Goji, get a JET ranking on all the Grind City levels.
Play as Gum - To unlock Gum simply finish her challenges at the beginging of the game.
Play as Love Shockers, Noise Tanks, Poison Jam, and Goji - Beat the game with a JET ranking in all stages. This includes regular stages as well as Golden Rhino stages
Play as Mew - Beat all the Benten-Cho (aka City of Night) levels with any ranking. After that, Mew will challenge you. Beat the three of her challenges, and she'll join you, allowing you to pick her as playable character.
Play as Poison Jam - To play as Poison Jam, get a JET ranking on all of the Kogane-cho levels.
Tab - Unlock Gum and complete the challenges Tab gives you afterwards.
Unlock Pots, the Dog! - To get to play as Pots, finish the game with the Jet ranking on every level. Every level, meaning both story mode and the basic areas.
Unlock Slate - Play through the game until Slate challenges you to a race in Kogane-Cho. Beat him to unlock.
Yo-Yo - Progress through story mode until he challenges you. Beat his challenge to unlock.