Not that great, you often find yourself doing the same thing again and again.
The battle system is turn based which isn't common in the online gaming world. Heres a basic summary of the battle system, on each turn you can move 3 spaces (more with special equipment), then you can choose from your skill list in the lower right corner, each attack has a certain range of use, so to damage the enemy they gotta be within a certain square distance.
Like your typical online game you can play it for 100s of hours to find yourself still at a low level, and accomplished nothing, this game is good at first but loses a lot of its play value when you realize how often you got to do the same thing over and over again.
I don't suggest people who are not into repeating game play to play this, but since its free you might as well give it a shot.