If you're already familiar with the Etrian Odyssey series and fan of the first two entries, stop reading now. This is the best entry in the series by far, and you should go out and buy this immediately.
For those who are new to this series or genre, it'll take a little thought on your part to determine if this is a game you'll enjoy. If you're the right kind of gamer for this game, however, I can just about guarantee that you'll absolutely LOVE this game.
Etrian Odyssey III is primarily a first person dungeon crawling RPG. It's got a bare-bones story that pushes you to create your own plots and stories as you play. The story overall is pretty involved and you'll meet a lot of interesting characters, but all the characters that you play are entirely of your own creation (from name to job to portait). To maximize the storytelling potential of this game, I highly recommend you take the time to create (and maybe even write down) stories for your guild and guild members.
Where EO3 really shines, however, is the gameplay. Character customization is the deepest in the series, and some of the best in the genre. You can create up to 30 different characters, and take a party of up to 5 with you into the dungeon. EO3 replaces the old classes from the first two entries in the series with 10 completely new classes. These classes are very unique and most are completely original (and not just a carbon copy of an old EO class). Within this class, you'll be spending skill points (you earn one with each level-up) to obtain both passive skills and skills you use as commands in battle. You can choose your character's name, gender, class, portrait (including 2 color schemes for each portrait), equipment, skills, and later in the game, a subclass. That's right, for the first time in the series, you'll be able to select a subclass and get most of the skills from class in combination with skills from your character's primary class. It adds a whole new level to customization and experimentation.
Exploring the labyrinth is simple enough thanks to fantastic controls (including the ability to slide sideways without changing direction with the L or R shoulder buttons). As you explore, you'll be drawing your own map on the touch screen. New to this entry is also the ability to draw a path of arrows on your map, which you can use for auto-walking. As you explore the labyrinth, you'll encounter enemies. Although they're technically random encounters, there is a gauge which changes color, so you'll rarely be surprised by battle. Battles are standard turn-based affairs, but tend to be very challenging and require a lot of strategy to win. You'll obtain items to sell and experience from battle, all of which are important to powering up your guild members as you progress through the Yggdrasil labyrinth. And of course FOEs (powerful boss-like monsters which roam the labyrinth) also return, and are back to giving out experience. Side quests are also available in the city of Armoroad, which are great for giving you something else to do besides exploring and mapping.
And if you need some fresh air, EO3 introduces sailing! Similar to exploring the labyrinth, you can now sail a ship on the open seas. You'll still be mapping them, but you won't be fighting any enemies while you sail. It's still challenging and requires some strategy, and you'll unlock quests which pit you against more challenging monsters (with valuable rewards, of course). Inver Port is also home to the another new element in the series--multiplayer elements. You can tackle tough battles with friends using local wireless, go into a "tag mode" where you can meet other guilds, or trade items with fellow explorers. The only issue here is that it's a very minor component, and can only be used locally (and not online). If you've got friends with the game, however, it's a great feature, if not a bit underwhelming.
EO3 continues tradition with presentation. Most of the game's graphics consist of gorgeous 2D art (the maritime theme really leads to some stunningly beautiful areas) and very detailed character portraits. The labyrinth and seafaring feature 3D graphics, all of which are perfectly functional if not attractive. You'll encounter some absolutely beautiful areas in the labyrinth, and I personally found them to be a bit more varied and interesting to look at in general. Battle animations are a bit more varied, and of course the monster designs are all fantastic and detailed. There's no voice acting in the game, but the sound effects are sufficient. And of course, the music is absolutely fantastic. It's got a retro sound to it, but the melodies are all excellent. If you enjoy the music in the game, I highly recommend listening to tracks from the Super Arrange soundtrack album, which feature these melodies played with actual instruments.
If all of this sounds interesting and fun to you, go get the game, because I'm sure you'll love it. If you're still not sure, I still recommend trying it out. It's very challenging and the presentation is attractive-but-simple, but it's a very deep and customizable RPG experience that will literally last you for hours. There's also a new game+ feature, which allows you to keep replaying the game with all your maps, items, and guild members, which means you can easily experiment with different parties, classes, and skill builds. Basically, if you enjoy RPGs and don't mind a challenge and lighter story, GET THIS GAME!
~QUICK READ~
STORY: Sufficient but barebones; this game is more about creating your own story.
GAMEPLAY: Fairly simple overall, but a lot of customization options. You explore dungeons/the ocean and map these areas yourself. Battles are standard turn-based encounters, but very challenging.
PRESENTATION: Again, simple, but still very attractive. Music is fantastic, major high point of the game.
LONGEVITY: This game takes a long time to finish, and the gameplay is customizable enough that it's worth playing through multiple times.
BUY IT: If you like RPGs focused on exploration, character customization, and tough battles.
DON'T BUY IT: If you're looking for an involved story, high-end presentation/graphics, or forgiving difficulty.