Go to "Super Heroes Mode" and in the map screen choose the 3rd option on top, then activate the following cheats by entering the corresponding passwords:

CHEAT FUNCTION - PASSWORD
Accel and G3-X vs Scissors - Ryuki, Kuuga, Decade, Agito, Blade, Kiva
Agito vs Rider 1 - Decade, W, OOO, Fourze, Wizard, Den-O
Den-O vs Odin - Kuuga, OOO, Blade, Kabuto, Agito, Wizard
Femme vs Ryuga - Kiva, Fourze, Den-o, Decade, Kabuto, Agito
Hibiki vs Ryuki - Wizard, Kabuto, Den-o, Hibiki, Decade, Faiz
Meteor vs Zanki - Ryuki, Wizard, Agito, Kiva, OOO, Den-O
Saga vs Blade - Faiz, Den-O, W, Wizard, Decade, Kuuga
Saga vs PunchHopper - W, OOO, Wizard, Den-o, Kiva, Fourze