The best part of Last Remnant is the incredible battle system, If you like to forge ahead farther than your'e relaly supposed to go, the game can get REALLY challenging. There are some hidden dungeons as well, and generally by the later half of the game if you keep doing this, every battle feels like a fight for your life and can go on for 15-20 minutes. JUST for a regular battle. The good thing is that obviously you rank(level basically) up ALOT faster, and it's ok to take this risk becasue you can save anywhere, anytime out of battle.
There's also ALOT to do aside from the main story, so if you do enjoy the battle system you have plenty of gametime.