Cant say too much about the game just yet only been playing for 4 hours, but as my first time being able to play the game i must say im VERY impressed so far.
You basically play as Valkrie, a Goddess who takes slain humans and recruits them as warriors for the on going battle with the gods in another world to prevent the world from being destroyed. The difference here however is you have an alotted time to complete the game before the final battle *in other words, 8 Chapters that consist of roughly 180 episodes*, the first chapter consists of 24 episodes which means you have to basically train up your previously fallen warriors within the episode limit before the very last episode within the chapter. After successfully entering various dungeons and leving up them, you must then send them to the other world to help the on going war. At the end of each chapter you are reported on how well that war is going on so far, obviously from time to time it'll only be a success if you recruit, train and send the warriors over their when they pass a certain level in their stats. Send them when they're too weak however, and they can die and possibly lead you to a bad ending in the game with Valkryie failing to complete her mission.
The game already has excellent Music and battles (which are turn based but require active use of pressing each of the 4 playstation buttons which are asigned to each character which really makes battle fresh, exciting and combo laden:) )
The stories you see with each character that eventually dies and join you are really quite dramatic was really surprised how much thought went into them, i can honestly say how these people died really helps you understand the characters feelings and really encourages you to train them up really well before the last battle with Ragnorak (last chapter in the game supposedly)
anyways, so far if you love RPG's and love a game with great character development, great battle music with excellent combat, you really cant go wrong with this game.
If you also want to play another great JRPG on the PSP, try the criminally underrated Tales of Eternia (known as Tales of Destiny II in America) which going for real cheap here on Play.com or other retailers.
Not an expert reviewer but i hope a managed to shed some light on this very promising game :)