This often-underrated game is a good choice for most ages. In spite of the combat-centric gameplay, it's blood-free, and the language is pretty mild. The story is enjoyable, with good characters and profound lessons that can positively influence young and old alike. Top it off with beautiful graphics and an amazing soundtrack, and a simple but nuanced control system (some complain it's too simple: the fact is that the controls are designed to be as simple or complex as your individual approach to gameplay, melding to the user's preferences).
A few thematic elements and disturbing creatures are perhaps the biggest concerns, but if you let your kids play Zelda or the more recent Mario games, there's no reason they can't play this.