Nightmare Guy Savage (as dubbed by someone on a Message Board) is a Mini-Game (or Demo) of a game on Metal Gear Solid 3: Subsistence for the PS2. Some think it's just a Mini-Game, while others think it's a Demo for an unreleased Konami Game. Whatever it is, it's fun.
The game is pretty gory. In it, you play the role of a man with two hook swords. Using them, you can dismember enemies in more than one way. After you've killed enough of them in rapid succession, the man will transform into a creature with Werewolf like movements, and gain claws in place of his hook swords. Using the claws, you can rip open enemies, and see they're rib cages. It's nasty fun!
I would personally love to know more about this game, and that's why I'm posting this. If anyone has any other information on this game at all, or if there's a game just like it out there, give me a shout in the comments or PM me.