A refreshing visual treat. It will be your new hallucinogen of choice
The gameplay is pretty simple. Using primarily the thumb sticks, you control a ball. mostly everything that is smaller than the ball can be rolled up into a clump (katamari) and add to it's mass. You start off small, rolling up thumbtacks and sugar cubes until you're eventually rolling up cars and trees. The fun doesn't stop there because eventually you get so big you're rolling up mountain ranges and astrological phenomena.
This is all done in full 1080i where there may be thousands of individual items in your katamari. The color palette is rich and the dialogue is just plain ridiculousness. A wonderful piece of eye-candy. The music is catchy as well
Overall, there's enough game modes and variety to keep you coming back for more, but the gist of the game is rolling up katamari. It's a fun, cathartic experience that I would recommend to anyone.