With Kamen Rider OOO's first movie-only Combo, the Kamen Rider OOO Tamashii Combo revealed a few weeks ago, here are more info the combo and some tidbits about OOO - Den-O - All Riders: Let's Go KAMEN RIDERS.
Kamen Rider OOO Tamashii Combo is formed by utilizing the Taka (Hawk), Imagin and Shocker Core Medals. It has the strong wrist power of Momotaros, and the evil power of Shocker, but this doesn't mean that the Combo is evil, it's just saying it's got the powerful energy.
The Shocker Core Medal comes from the Taka Cell Medal that Ankh dropped when they traveled back in 1971, chasing the Mole Imagin. It contains the energy created by the scientists and increases the attack power. The horns on the shoulders of the Tamashii Combo can be used as a weapon, but Momotaros thinks it's just a decoration so that OOO can fight "in a stylish way."
OOO Tamashii Combo's finisher is called the TaMaShii Bomber which utilizes the power of the three Core Medals and throw a spiritual ball ala "Kamehameha."
In addition, the last image above is a shot of Kamen Rider NEW Den-O's MacheTeddy. Teddy was trapped in 1971 when trying to save Naoki. Meanwhile, when Momotaros returns to 2011, in the final battle, he sees the secondary Riders, lead by Kamen Rider Birth, help the main Riders. Also, the third image posted above is the other appearance of Shocker's Great Leader which was first seen at the end of Kamen Rider Stronger.
Source: KamenRiderUNDERGORUND of HJU