(Written from perspective of a level 15 warrior)
Easy to get into, simple and intuitive controls are good for playability but the technique is more than just "mash buttons until everything's dead," although that is my play style as a solo warrior... Definitely more fun than WoW so far, although I have yet to see how the late game is.
Art style is nice, I enjoy the overdone attack effects and the silly-but-still-dangerous low-level enemies.
It seems a little on the easy side, I can solo dungeons on hard with little difficulty (adrenaline is another matter, however) but I can see where parties will be helpful, especially for non-warriors. Gobarta is no sweat, I can tank through it pretty easily but there's still that level of difficulty I like.
Overall, a cool little game that's totally worth the low, low price of $0.00.