It's an immensly fun game that I got hooked on the minute it finished installing. Seriously. You'll see what I mean if you do try the demo. Go here for a review and download links. Yes, sadly it is only a demo, but will be available for purchase on their website aswell as on WiiWare for 1500 points.
It's also available on the PC, and I would recommend you get it. The PC version may (may!!) be getting a bonus chapter in a few months. Plus, you get detailed leadeboards. For those who may not get it, it has a 9.5 on IGN, and near-perfect scores all around.
I really want to. I'm probably going to head out and get a visa giftcard to use to buy the full version. My dad would never put his CC number on the internet.