Rowan Kaiser: "Smoothness" isn't a common criteria used to judge games. If anything, it's the opposite. Getting the difficulty level just right, so that the game seems like a challenge but is completable with practice, seems like it's an ideal. Or, you can use Sid Meier's model of games as "interesting choices" – but if the game isn't challenging, those choices don't seem to matter, right? I think acceptance theories like those are part of the reason that Japanese role-playing games are considered less important than they used to be.