As it gets longer, it'll become less hard.



Wait, I want to rephrase that. You can blast through the game in fairly standard FF time, avoiding all the side areas and missions. This will be make the game more difficult, as you will likely miss out on some of the most useful equipment and spells etc, not to mention you'll be underlevelled. If you take your time and explore all that this phenomenal game has to offer - which is a substantial amount - you'll probably sink over 100 hours into it, and you'll find it a really fulfilling and rewarding game.