This game is full of characters galore, but it is what you do for those characters that falls flat.
Basically here is how the gameplay works out you will be thrust into an open world filled with monsters that are typically around your level range. You will be equiped with a ranged weapon most of the time and combat involves you picking a Nano (a small version of one of Cartoon Network's famous characters) and holding down the left mouse button till the enemy dies. Sometimes in boss fights you will have to do the above while dodging an area attack, though most of the time the only factor of you winning is your level and the weapon you have equipped. So most of the time you can guess if you will win a fight before you even enter it.
The Grigon team that created the game tried to throw in a twist though in the form of each of the Nanos you collect grants you a certain power of your choosing. These powers can range from being able to run faster, jump higher, appear invisible to enemies, and many more. These powers turn out to be a nice twist for a little bit, but you will find that once you have a set roster of Nanos that you use, you will be using those Nanos for the rest of the game. This is because as you level up and find new Nanos they don't really level up, all they really do is offer you a chance to get a new power that you might not find useful. Essentially the Nano section of the game is a nice little add on towards the beginning, but when you get into the later sections it just seems like something you really don't have to deal with.
As for the story, there is a small glimmer of hope though don't be expecting anything too deep. Depending on the Mentor you choose at the beginning of the game will determine which storyline you will follow. These are just one out of the MANY of missions that the NPCs in this game will set you on. They can range from killing a certain number of enemies to going and disarming gooby traps in the many obstacle courses set up around the world. These may sound fun and they are towards the beginning of your time with this game, but soon you will start seeing many missions repeating themselves quite often but with a slightly different story behind each one. You may like killing those Candy Ninjas now, but you won't like it when you have to kill them for the 5th time in a mission you need to do in order to level up. Basically in the end, the game tried really hard to be something big, but in the end it falls flat. The reason I gave it a 6 in my review is because you do have to keep in mind this is a child oriented game and should be treated that way. Don't play it expecting anything real deep.