The codes below have been tested in Normal difficulty.

Unlockable	How to unlock
Play as Douji & Hime of Ittanmomen	Beat 1P Battle Mode once.
Play as Douji & Hime of Yamaarashi	Beat 1P Battle Mode twice.
Play as Kamen Rider Armed Hibiki	Beat 1P Kiyome Mode five times.
Play as Kamen Rider Danki	Beat 1P Kiyome Mode three times.
Play as Kamen Rider Hibiki Kurenai	Beat 1P Kiyome Mode once. When you play as Kamen Rider Hibiki (except in Kiyome Mode), hit L1 in battle. Hibiki then transform into Hibiki Kurenai.
Play as Kamen Rider Sabaki	Beat 1P Kiyome Mode four times.
Play as Kamen Rider Zanki	Beat 1P Kiyome Mode twice.
Play as Midaredouji	Beat 1P Battle Mode five times.
Play as Super Douji & Hime	Beat 1P Battle Mode three times.
Unlock 2P Makamou Taisen Mode	Beat 1P Battle Mode four times.