If you're looking for a trip back to the old school days of dungeon crawling, you'll enjoy this one.
Etrian Odyssey address this by bringing back the dungeon crawler to the extreme. Why do I say extreme? Atlus wanted to provide a game that didn't have a lot of bells or whistles. Even the story is severely lacking for a RPG. You play as a person who is setting up a guild so you can design any characters from scratch from nine different classes. Two of them will be available later but there is still a lot of customization. Each class, when they level, will also give your characters the ability to choose a new ability.
It is an adequate looking game and the colours are very vibrant. Unfortunately, in battles, which is what you'll be doing most of the game, there are almost no animations. Other than your hp bar shaking a little bit or your sword, represented by a line going through the enemy, there's nothing else to talk about. This is really quite unfortunate because at the beginning of the game, it looks like it could really utilize the DS capabilities.
One aspect of the game is the map. Everything is in a 3D view when you're in the dungeon and it looks good. The trees are generally flat and other things in the background pop up out of no where when you get close enough but it's nice to see something like that on a handheld.
The game took me a long time to finish but there's many side quests and different items to get so there is some replayability.
This is probably the best dungeon crawler to come out in a long time. If you're into grinding and gaining levels with a hefty challenge, this game should be for you.