Echoing what others have said, it's not necessarily a difficult game but it's certainly a long one. Ironically, the way the game is set up, it's much less stop-start than the previous entries which had random battles. I think it's very much a game you can make as long as you want, within reason. If you like exploring, getting various Espers and hunting the marks, then that'll considerably lengthen your game. It's the only FF game I think I've ever clocked up 100 hours on in one playthrough.