Bonus items

Enter OKHYTRG781N6XKN0 as a code at the item shop to get 30 Rewinds, 30 Ultrasounds, and 30 Swansongs.

Luna and several other items

Enter OKHYTRG781N6XKN0 as a password, then HDTM QBBN 2QRG XNJJN KGF4 YW32 MZTT7 2NA9C as a password.

Secret Troops

Available only after clearing all previous Rehearsal Room Modes.

Iron Man Archer : Clear Ultra Mode in the Rehearsal Room with an Archer as the Enemy.
Iron Man Knight : Clear Ultra Mode in the Rehearsal Room with a Knight as the Enemy.
Iron Man Mage : Clear Ultra Mode in the Rehearsal Room with a Mage as the Enemy.
Iron Man Monk : Clear Ultra Mode in the Rehearsal Room with a Monk as the Enemy.
Iron Man Soldier : Clear Ultra Mode in the Rehearsal Room with a Soldier