Metal Gear Rising is the lovechild of two very different development studios. Kojima Productions is known for their PlayStation bias, as seen in the perpetual PS3 exclusivity of Metal Gear Solid 4, and the development of Castlevania: Lords of Shadow. But Platinum Games has most of their experience on the Xbox 360, having opted to pass on development duties of the PS3 version of Bayonetta to an external studio.
So, what's happening with Metal Gear Rising: Revengeance?
Rising was originally developed on Kojima Productions' new multi-platform FOX Engine. However, when that game was canceled and handed over to Platinum Games, the game was retooled with Platinum's own proprietary engine. Apparently, since the development of Vanquish, Platinum Games always makes PS3 the "lead platform."
Some fans noted the use of Xbox 360 controllers in the documentary video released yesterday. Inaba clarified that the lack of PS3 controllers was due to the lack of official PS3 controller drivers for PC. The Xbox 360 controller is the only official option when developing multiplatform games on PC.
Unfortunately, since Revengeance's re-reveal, a PC version has yet to be mentioned. The original Rising was meant for PC, PS3, and Xbox 360. Konami currently lists Revengeance as a console-only game.