Photo of the Metal Gear Rising Game Over Screen
Today, Hideo Kojima was checking out the trial version of the game. He posted a photo on his Twitter of the menu you get when you die.
Note that the Game Over message still says ‘Mission Failed’, in the same font as the other Metal Gear games. You can return to the title screen from here, or reload a checkpoint.
Kojima wrote ‘Raiden 3D’ alongside the photo, and laid out the arm so as if it is sticking out of the tv. Could he possibly be hinting at the game being playable in 3D, or is it merely a joke?
Source: Hideo Kojima’s Twitter

Raiden ?answer me! Raiden?! Raideeen !!!!!!
What is this Raiden arm he keeps showing? On one of the pictures he posted, it almost seems like a black usb cable coming out of it.
It’s a promotional item Kojima Productions had made (there are a few, and they sent them to some select people, like the Platinum Games staff). The cables running out of it refer to the fact that apparently in the story, they are using Raiden’s cybernetic arm to extract data. The teaser site also represents this.
I hope the hand is included in a collector edition or something like that hahahah