The Metal Gear Solid games have taken some bold turns. A couple of their boldest are on the PSP. Metal Gear Acid was – you'll never believe this – a mix of turn-based strategy and a collectible card game. And now Peace Walker is a bunch of stealth missions linked together by a finicky base management game. It's a bit like X-Com, or maybe those sports management games, or perhaps Disgaea, but also unlike any of those.