This game is just an absolute non-stop blast. I actually played the original PC version of it years ago, and this version is every bit as good as its PC counterpart. The graphics look slightly different in the PSP version but it's lightning quick, as anyone who's played Ys IV: Ark of Napishtim's PSP version can identify as a positive change. There's barely any loading between areas, the framerate never even approaches dropping, and the whole presentation is just top notch.
Many people have praised the voice acting. I'll agree, it's definitely competent, but some of the choices are a bit cheesy (and like a lot of B-tier videogame english voice-overs, overdone). I don't know if I got used to it or if it picks up as the game goes on, but I actually found the story moments late-game quite captivating. I've actually been playing the series since I was 6 or 7 (the original MS DOS conversion of Ys Book 1) and Ys 3: Wanderers from Ys was one of the first games I played on my SNES as a kid. Suffice to say, this game has almost everything from the first game, expanded about 500%. Dungeons are way longer, with tons of alternate routes and treasures strewn about. The overworld serves to quickly move the action between dungeons, and the main town is good-sized enough to offer a few quests off the beaten path but never so big that its navigation becomes a chore. The pacing is pretty good, with a pretty steep spike on every boss encounter. There are a ton of difficulty options--the highest, 'Inferno', is locked until you beat it on Nightmare. This will not be easily done.
The battle system is just plain glorious. X attacks, which combos into 6 hits upon repeated mashing. Attacking without pressing a direction on the stick will kind of auto-direct the attacks to the closest targets, making it easy to smoothly execute large amounts of foes. The game handles jumping attacks quite intelligently too. You have various attacks that can be performed aerially, dependent on whether or not you're holding a direction and what side of your jump you attack on. On the way down? Falling area attack that hits on all sides. On the way up? Moving? Quick strike that lurches you forward. Not Moving? Spinning attack that does damage to flying creatures. It's awesome--simple enough to allow ample use of every attack type, but fast enough that it never gets boring. Falcom should truly be commended, as it's just a fantastic battle system. On the easiest difficulties, enemies are limited in attacks and have low health, allowing you to breeze through dungeons relatively unscathed. On normal difficulties, you'll probably get to save points before you get hurt (due to the health items enemies drop) but it stays engaging. On Nightmare, you will rutinely die in some of the later rooms--making the game's great design that much greater. If you die, you can respawn from the entry to that room. If you die on a boss, you can retry him (and you will....oooooh you will). If you die a ton on a boss, you can swallow your pride and lower the difficulty. It's like Falcom made a checklist of every good feature that's ever been in a game, streamlined them, and combined them into a fast paced party of a game.
Keep in mind--if you're into beating games on their hardest settings (especially the first time around), be prepared to die a ton of times on most every boss. Assuming you aren't leveling to the point of killing any difficulty, boss attack patterns are fast, vicious, and constant on every single boss. Most require several minutes of perfectly-timed play to even have a prayer of getting through them....2 specific bosses come to mind where I'm sure I died in excess of 50 times. It's manageable difficulty in every case, however, and barring 1 or 2 instances of...irritating boss mechanics, it's truly a gem of a game boss-wise. It took me about 20 hours to beat the game my first time on Nightmare--at least it said that on my file. Counting the retries on bosses, it was probably closer to 25.
If you own a PSP and you don't own this game, I don't know what you're playing on it. This and Ys Seven are both must-own titles and truly show why the PSP is the absolute pinnacle of portable entertainment currently.