According to ESRB, this game contains: Blood, Partial Nudity, Violence
Parents will want to take into consideration that the game is rated for Teens. There's nothing particularly offensive in the game, but it does feature a lot of fighting, some blood, etc. Perhaps more important is that the game features a steep learning curve that is sure to frustrate younger gamers. Dragon Quarter is inappropriate for most pre-teens simply because it's a difficult game.
RPG fans will certainly want to give the game a shot, but the more traditional amongst us would be well advised to prepare for a radical departure from the norm. This isn't your father's Breath Of Fire, after all.
Casual gamers should probably take a rent-first approach, as the game is rather quirky and will not appeal to everyone. Aside from that, the relatively short play time means that it could be easily beaten in a standard rental period.
Deaf and Hard of Hearing gamers have nothing to fear (other than missing out on the game's beautiful soundtrack) as all of the dialogue in Dragon Quarter appears onscreen.