This game features a ton of great game elements, but still feels lacking in certain aspects.
It was actually the battle system that drew me to this game, playing the demo I noticed that it was fairly original and that was enough to sell me. Enemies roam around dungeons and whatnot when you make contact with them you initiate a battle and go to a battle screen. Normal rules apply to this method, you run into the back of them and you get a back attack advantage and vice versa.
On the battle screen it goes in a turn based fashion where you are always aware of who is up next. However, each turn is not a one move turn. You have limited time to perform whatever actions you choose. At the start you'll have something like 2 seconds of "tactical time" (aka time to think) and then something like 4 seconds of "action time" (time to do). These times change as the game goes on and you become more experienced.
During the action time you can move, attack, throw up items, and whatever combination of these you choose. Four seconds doesn't sound like a lot, but it's really a good amount of time to do some damage. Once you start to figure out enemies and their patterns you can really utilize this time and take out enemies before they even get a turn.
The game also features special attacks that you can use at any time. These take X seconds to perform and are things like stronger multiple hit attacks or magic spells. Not long in the game though you'll find that if you are in the middle of a combo when your action time runs out you'll still finish the combo and you can spam your special attack and still pull it off effectively using more than your allotted time. This is where some of the downfalls come in, but more on those soon.
The other really cool thing that Eternal Sonata incorporates is the use of light and shadows. These come into play in two different ways. One is that enemies will sometimes change into different (more or less powerful enemies) when they move from light into shadow. The other is that you're characters have different special attacks when they are located in the light or the shadows.
Now, these light and shadows aren't just like full fledged light or dark areas, but when you are in a battle often there will be lights around that emit light, or maybe the whole area will be light but you can get in the shadow cast by an enemy. Or some enemies have lights of their own. There are items that emit a light (or shadow) around you for a period of time. This is incorporated all kinds of ways and is really cool.
The graphics in the game are amazing. Obviously it doesn't shoot for a realistic feel, but the characters models are great, the environments are great and there is all kinds of flashy effects. The sound is pretty good. The music is good (as it should be, being about Chopin), but some of the sound effects feel a bit off.
Now, the downfalls, which happen to be some of the games coolest things. The battle system is awesome, I loved it. But, it gets to the point where you can perform so many high combo-high damage moves that it gets monotonous. You'll find that after about 3 encounters with any type of enemy you'll have a plan mapped out of how to defeat them in the fewest hits and you'll use that same strategy for the next 100 encounters with that enemy.
The game is also pretty easy. Maybe my characters got over-leveled, or maybe I should have switched up the characters I use more, but really the only parts that aren't a breeze is the bonus dungeon towards the end of the game. After going through which you will completely OBLITERATE the final boss.
The story segments often drag out for way to long as well. I liked all the characters and I wanted to know their stories. But there is so much dialogue that after a certain point it's very difficult to pay attention any more and absorb what you're being told.
If they had toned down and balanced some of these things a little better I think the game would be almost perfect. I really liked it a lot, I just feel like it wasn't balanced right. That's the best way for me to put it really. But, if you own a 360 and like RPG's there's not much else to choose from. I say give it a shot, just to have a good time and maybe force yourself to vary things up a bit because the game won't force it upon you.