... his "director's diary" in "columns" at the official website may be quite informative if you don't know anything about the genre.
I find that this comic provides a great description of the game as well. "It's dungeon training!"
I played the game a few months ago and I'd say it isn't so much ass demoloshingly hard as it is extremely unforgiving (yes, there is a difference). Once you get used to the fact that there's no quick save, you become much more careful/paranoid and better prepared for the harder fights. There's also a level cap to contend with, but that doesn't factor in until you're near the last few floors anyway. Some of the optional bosses will also test your patience, but again, they're optional.
Ya know, I just realized that the last time I was killed in the first area of an RPG was Lunar 2: Eternal Blue Complete, and I'd say that game's difficulty level is a pretty fair comparison for the amount of difficulty present in Etrian Odyssey. Then again, Lunar allowed you to save anywhere, while EO doesn't.
Anyhoo, whether or not you get the game, make sure to watch the FOE music video: http://youtube.com/watch?v=Kbnu0NKs86Y