Friends can join in the game by taking control of the blue spirit. While hardly as big an experience as other co-op games, it's interesting, especially when you work together to solve puzzles or blind an enemy that blocks Aurora's path.
Child of Light has a unique battle system that totally clicks. Rather than having players grind over mindless battles, this game has a meter at the bottom of the screen, which gauges whose turn is next. During turns, you can time your counter-attacks to slow or interrupt an enemy, in which the meter then comes around to you again, allowing you to strike with a number of abilities. It's a fair system that works especially well at higher difficulties.
As you progress in Child of Light, you'll work your way through a skill tree, unlocking new abilities (without having to grind for them, thankfully) and eventually making your party a force to be reckoned with. Again, it's quite fair, and gives more than enough drive to keep you going well later into the game.
The main downside to the game is that the AI on the normal setting doesn't put up much of a fight. An enemy might have you on the ropes, but then your blue spirit can restore all your energy. If you want a real fight, go into the harder difficulty setting. It's here that you'll really master what the battle system has to offer.
The game's characters are well defined here
Where Child of Light will really hook into you is with its presentation. The soundtrack is perhaps the most compelling we've heard from Ubisoft Montreal to date, and it stays within the flow of the action, whether you're somberly visiting a village or jumping head-first into battle. The art style is wonderful, with a beauteous hand-drawn quality in both the backdrops and characters. The little comic nuances are a nice touch too, particularly the drunk birds at the bar.
One side note, the dialogue is... interesting, to say the least. The writers of the game felt that
Child of Light provides tremendous amounts of beauty