Shinobi for the PS2. Basically, the only way the game "challenged" me was to throw me up against mobs of enemies that could block every attack except for the right moment, when you had a split-second to do something or you'd take a wakizashi to the throat. That's too hard. When a game basically can't challenge you in any way other than saying "OK, this enemy is absolutely impossible to damage except right before his attack, at which point you press X to hurt him, or else he takes away half your life bar." Sure, some people may argue "reflexes" or "learning curve," but every game, in my opinion, ought to be able to challenge you without tossing invulnerable badguys out of the walls.