It's a well-known fact that ninjas are cool. Yet these enigmatic, highly trained, highly disciplined, emotionless Japanese assassins probably have a pretty difficult life, what with all the skulking and assassinating and running around. And in the case of Shinobi, Sega's latest 3D action game, the main character, Hotsuma, has it even tougher than usual--he'll be constantly fighting off the demonic remains of his former clansmen. So if you're expecting a challenge from Shinobi, then at least you know what you're in for. The game, inspired by Sega's classic ninja action series, is notable both for its extreme level of difficulty and also for its highly responsive control mechanics. The combination of these elements makes for a game that can be very satisfying when it isn't frustrating, though in any event, Shinobi could have used more time in development so that its action could have stood out better from the game's assorted shortcomings.