In order to clean up the mess caused by a
drunken galactic king evil galactic prince, the tiny protagonist protagonists of Katamari Damacy Tornado must roll up pick up lots of stuff, including trees and buildings, in a big ball tornado. As you pick up more stuff, your ball tornado increases in size, allowing you to pick up bigger stuff.
Of course, Katamari Damacy didn't have adorable furry characters (to its credit), and it didn't require players to constantly spin in a circle to generate momentum. Other than that, the two games look pretty similar. But if Tornado is a well-executed ripoff, we'll probably still be interested. We are slaves to rolling-stuff-up gameplay.