The game is a little hard to understand but still oddly fun to play with.
From what I gather...You're that little gray faced guy with the crown. Your job is to get stuff to stick to you. Eventually you are part of a big ball of stuff that clears the screen to reveal a pretty picture. I think that might be level 1 but since it's in Japanese it's just a guess on my part - but you'll figure it out.
I pulled this off the Amazon review by J. Roberts aka R.P. Madman -
"For those who don't know, in Katamari games you control a super-sticky orb (a katamari) that rolls throughout a world packed with stuff. Roll up enough caramels and you'll be big enough to roll up a mouse. Roll up enough mice and you can roll up cats. And so on, until you're rolling up clouds, islands and thunder gods. All this is built up over the course of a few levels, but it can be disorienting to roll up cookies under a car at the beginning of a level and roll up the car itself in the end.
With each level a new star is added to the sky (replacing the ones your monolithic and rather drunken father, the King of All Cosmos, accidentally destroyed)."
