I really like this game, and I don't even have kids. The characters are simple to put together, and easy to meld into whatever the player wants by allowing them to choose their "shines" (things they're good at), a weakness, and their One Special Thing--a powerful, but finite, resource to draw upon, which could represent a special item, a pet or follower, or an intrinsic ability or power. There are also 3 stats, rated 2-4.
The core mechanics are pretty standard dice pool roll-and-keep: the most appropriate stat makes up the base of a d6 dice pool. Add a die for any applicable shines, and remove a die for any relevant weaknesses. Roll 'em, and results of 4, 5, 6 each count as a success ("star"). 1 star is usually enough for a marginal success, and more is obviously better. Contested rolls compare the margin of success between two opposing rolls. The One Special Thing contributes automatic successes, up to 5 per session/adventure.
What I really found novel about this game is the way they handle "fights" and similar contests, where the goal is to take someone or something else out of the scene, and risk be taken out of it yourself. It's a lot like Fate, but with a simplified Stress/Consequences mechanic that I found really elegant. Essentially, a fight is a bunch of opposed rolls, and the margin of success on an attack (or any other action geared at overcoming the opponent, such as intimidation or trickery) is taken as Damage to the defender, who has a finite amount of Damage that he/she/it can take before they're knocked out, chased away, captured, whatever.
Here's where it gets cool: the players get to decide how much they really care about the fight before it even starts, by choosing how much Damage they can take before being taken out. That is, they get to choose their hitpoints/stress for each battle, up to the default limit of 12. Why not always choose 12? Well, if the character takes damage in excess of their highest stat (usually 4) during a fight, then the character is Hurt, and takes a -1 forward to all rolls until healed, as well as a new Weakness that lasts until the end of the adventure. By setting your Damage below your highest stat, you're immune to those serious consequences, but at the risk of being knocked out early. I think that's an interesting way to signal "Hey, I really have a horse in this race...10 DAMAGE until I'm out!" or "I'm going to play it safe, here...3 Damage," or "This is really Bob's fight, not mine, but I'm a staunch ally, so...6 Damage."
Character progression happens organically: if a roll produces all successes, you get to add a new Shine, or bump up the ones you have by a point. It probably goes without saying, but the worse you are at something, the fewer dice you chuck, the more likely you are to improve. Simple, but produces a familiar curve, without tracking XP or other nonsense.
Since One Special Things have finite uses, they make ideal treasures and items for the GM to reward players with without having to worry about overpowering them in any permanent way.
Overall, I think FirstFable does a lot of what Fate sets out to do, but in a much more intuitive fashion. I actually think that this game might replace Fate Accelerated Edition as my go-to one-shot and introductory RPG for grown-ups.
[5 of 5 Stars!]