A game for game's sake.
The game starts off with your father, the King of All Cosmos, getting hammered one night and accidentaly destroying every star in the sky. To put them back, he has assigned you, the Prince of All Cosmos, to replace them by traveling to earth and rolling them up in the sticky ball known as the "Katamari." The story gets a little strange from here on. Interspersed inbetween the levels you get mini cutscenes which follow a family around as they witness your damage.
The gameplay is as simple as it sounds. You roll a ball, over stuff, and....no, that's it. You just pick things up. You control the Katamri with the two analog sticks, and try to pick up as many things as you can in the alloted time. You also need to grow to certain sizes to pick up bigger things, (the bigger you are, the bigger object you can pick up).
Each level requires you to get to a certain size. However, there are also about 5 or so levels where you build constalations and have to find certain objects, (the biggest bear you can find for Ursa Major, women for virgo, etc.).
The game goes through these levels prety quick, and it is not too hard to run through it in one sitting. But this quick pace really gives you a good evolution of size. The first levels start you off inside a home, as small as an ant. And the last level has you rolling around the world, eventually growing to the size where you can pick up whole islands and clouds.
But in essence, it's about the experience, not the difficulty and length of the game. While level goals are the mainstay, you'll feel a powerful urge to go through every level to become as big as you can. Also, hidden in the levels are gifts left by the King, which are accessories for the Prince to wear. You also find your cousins, which are more playable characters for the 2 player vs. mode.
The soundtrack is as addictive as the game itself. Filled with quirky tunes, most of them written for the game, the soundtrack fits the oddities of the game perfectly. They run the gauntlet from electronica, to dance, to be-bop jazz.
It also has a very unique style. It's as if they built everything from digital legos. But really, this game just wouldn't have the same feel if it tried for crazy graphics, so in the end it's a good thing.
As simple as it is, Katamari Damacy is easily one of the most innovative titles for the PS2. Instead of flooding the console's already full library with useless action/adventure-ness or a useless, patronizing story, this is truly a game for gamers. It's quick, it's fun, it will make you laugh, and you'll never forget it.