Picked this up for PS3 on the PSN for $5 the other day.  It's basically Tetris meets Katamari meets environmental awareness, and it's incredibly addictive, if somewhat difficult.  Sony put up a demo on Thursday, which I highly recommend all PS3 owners check out.  Plus, it gets bonus points for being yet another Japanese game to use the most overused rap lyrics in all of videogamedom (causing much mayhem).

I've only played it a few times, but yeah, it's pretty hard. It took me a while to figure out how to decompose the trash. Wished the game came with a tutorial. I think there's a tutorial vid on PSN...I have to check that out.

Grabbed it as well, but I have yet to put any real time into it.