The staff review is spot on as far as gameplay, graphics and more, so I won't rehash that all.
I have a two year old son, and my wife hates when I play any violent games for fear of my son watching them. However, after seeing the cartoony "voilence" of this game, she was aok with it, as was I. My son loves to watch the game for the unique characters, colors and music. The "violence" is pretty silly and over the top - like grabbing a skeleton with a rubber gummy whip and slamming him into a wall until he flies apart into his component bones. There's no blood, no language, no screaming in pain when an enemy hits you (or you hit them) and nothing even vaguely realistic about the game.
It's a good game to have around if you have kids. My son loves to call out where "bad guys" are, and he sits with his own unplugged controller, pretending to play. He loves this game, an frequently asks for me to play it.