I've finally got my copy today (50 bucks, ouch).
The game is indeed brilliant.
This is by no means an epic title that makes you go "WOW". The concept is very very simple - basically throwing a ball and blowing up blocks. No brainer, I thought. During the tutorial, I couldn't see what's so special about this. It was a little underwhelming.
But after an hour or so, I've found myself not wanting to stop. Eventually my wrist and arm started to hurt, so I finally conceded.
The game is deceptively simple and casual. I can see a lot of core gamers dismissing the game simply because it looks like another shovelware.
But the gameplay has a lot more depths and complexity than people might think. I, as a 30-something avid gamer, can easily see myself playing this for a long time, with both solo and co-op with my pals.
There's something innately fun about blowing up carefully-built structures and creating a chain reaction. It appeals to our very basic sense of fun, which we experienced as a child. During the play, I've kept smiling.
I like the fact that this game fully exploits the Wii's strength. It is practically impossible to realize the gameplay without using the motion-sensor technology.
After I took a break, I kept thinking about the game. It's addictive. In fact, I want to stop typing right now and go back to play.
Thanks to those in this thread who recommended this gem.