The most fun playing a video game you can have.
The real drawn to the game is the art style. The game is beautiful and the levels are unique. And if you don't like the ones you are given, then make your own. The simplistic controls are what really make this the greatest. You just run through the level grabbing things, jumping, or falling with style.
The story is cute but nothing memorable. Sack boy is the coolest character though.
The difficulty increases quite well in the main game. I never felt bored playing this game. It is for newbies and hardcore gamers, and even old people can play too. It's fun just watching everything happen that you forget your playing at times.
Now for a little negative. This game is only at its peak with friends. Playing alone just isn't as much fun. And it would be nice to create your own clothing or even play as different "Sack Boys" like a bean bag type one or pillow. :]
In the end this game is so much fun for everyone and anyone. Get it now and help them make a sequal in the future.