Quite cool racing game:)
It has a super gameplay I would say. You can choose one of the 3 types of characters wich are speed, fly and power. And each of it has a bonus in each map. You can take different advantages that require the atribute you choosed. You also have the possibility to buy better gears. You will unlock new maps missions characters. You may receive decorations and so on. I say again that it has an apreciable gameplay.
About graphics, well the graphics are average for a racing game. Although it is a recent game...it should have a better graphics. I can't say I am dissapointed about the graphics, but it could have been better.
Sound; I'll start that each character has a word to say, the maps have each it's own music except the upgraded maps that are later on...And yeah there are different sounds when you do other stuffs. Hmm... I say it has a decent sound.
Well about it's value I am not sure. As I said you can play this game anytime in multiplayer.