This entry in to the long-running series appearing the US summer of 2010, is a strong action-RPG worth consideration.
This time, Adol and his hetero life-mate Dogi have ended up in the port city of Altago to do some sightseeing and pick up some souvenirs I guess. Naturally, he ends up the hope of the entire population when he is called by the King of Altago to investigate some mysterious ruins outside of town. Nice work, if you can get it.
The first and most important mechanic of this game is the fact that Adol is no longer alone in his quest. Up to two companions will join him at any one time, and swapping between controlling them in the field is accomplished by a single button press. When not in control by the player, they run on a very simple AI that will attack whatever you are able to successfully land a hit on, and will use one of their skills whenever you do. Switching control is critical, as each character specializes in one of three damage types, each of which is useful against different types of enemies. In addition, each character will develop their own set of special attacks which get stronger with use. Each character also impacts the party in general, for example, by providing you with more money per kill or more experience, or faster skill charging. And finally, each character has their own unique "Ex Skill" which charges up through both through skill usage and successfully blocking attacks with a reflex move called a Flash Guard. Ex Skills mostly revolve around doing either a bunch of damage to multiple targets or massive damage to one in some sort of flashy manner.
The addition of the Party system is fairly revolutionary for the series and works out in its favor. Switching party members is simple, and juggling their stats and equipment adds a level of complexity to the game not seen in prior installments. Building up each character's skills is a rewarding experience and maxing everyone out is a fairly decent time-sink. It is also an imporant skill to learn the best times to switch characters in battle to take the most advantage of a situation (long range attacks versus strong attacks versus quick attacks) in order to maximize both damage and skill gain.
The story at large, as far as I can tell, is not much more than a typical Ys story of Adol saving the world. However, it is told with sincerity and seriousness, and characters which you may have thought you pegged turn out to be something else entirely over the course of the telling. It drags a bit towards the beginning, but it picks up about 1/3 through the game.
The pacing of the game can be a little tough at points. Battles against normal monsters are usually between two or three at a time at most, while prior entries may have you fighting more monsters. In addition to the predictable and limited enemy placements, the dungeon designs themselves for the most part are just squares connected by straight lines. There are a few exceptions, but you'll find the dungeons getting somewhat repetitve, but the environments are varied following the natural elements.
Despite this, each dungeon ends with a very satisfying boss battle that will defeat you multiple times. You'll have a rough time until you learn their attack patterns, what gear to equip, and who best suits the particular battle. Even then, you'll need to bring your A-Game to not get squashed flat, especially on the harder difficulties. However, the bosses never feel cheap or unbeatable, and downing them is worth a pat-on-the-back.
The music, in typical Ys fashion, blends classical instruments and rock guitars along with synth to create a memorable soundtrack. Notable standouts are Innocent Primeval Breaker (the opening theme song) and Vacant Interference (the boss battle theme). You might not like the soundtrack if you're not in to screaming guitars or fusion rock, but otherwise you'll enjoy it on some level.
The graphics, while fully 3D, lack the same sort of clarity and art that the former 2D sprites had. However, they are still pleasant to look at, although they won't blow anyone's mind. On the larger beasts or different camera angles, the PSP starts to show its limitations with chunky polygons, but those times are rare. Each character's weapon will change depending on what they have equipped, but their overall design will remain the same regardless of armor.
In sum, anyone that IS an Ys fan already is going to get this game. If you're a fan of Action RPGs in general, then this game is definitely worth a look. Rent it first naturally to make sure you're willing to spend the 20-30 hours the game will offer you on a full purchase. But I don't think you'll be disappointed with the amount of monster hacking, boss slaying, villain thwarting, and girl rescuing this game provides.