For those on the fence about buying this, the EX dungeons aren't even unlocked until you complete the initial story.  Granted the initial story is VERY short, there's a lot of good gameplay there that imo is enough to purchase the game.  I plan on playing through it again.  The EX dungeons, I think, are supposed to be a hard-as-nails bonus, like a throwback to the games of yesteryear.  So I think it's appropriately devilishly difficult.  Also, from what I've gathered, it's been completely developed in-house, meaning it's the work of our own forum members, which is pretty bad-ass.