Metal Gear Solid: Peace Walker is going to be big. And by that, we don't mean "successful," even thought it seems to be the only PSP game anyone's interested in anymore (or was, until God of War: Ghost of Sparta was announced). No, we mean that the game itself is huge. To wit, we recently spent a whopping 16 hours playing through its story, both by ourselves and in co-op mode with other journos, and it barely feels like we scratched the surface. There's tons of stuff to do and collect, and the game kept unlocking new modes and options after we thought we'd played long enough to open up everything.