This is (at this point) one of the very best Nintendo DS games out there, but yeah, you gotta love pinball.
In a nutshell, there are a total of six boards you play as you take a pinball-game-approach to whacking Mother Brain. Achieving one of the many sub-objectives on each board gives you an artifact, until finally you qualify to compete in the Artifact Temple.
All you *really* need to know is that there is quality fun to be had with this game. After having owned it for many months and fallen in and out of playing it, I surprised myself by scoring a personal best of 16,531,500 (over two morning busrides). This was after not having played for around a month. You'll find you get the knack -- the feel -- for the boards so that sporatic play-times still yield ridiculously fun results.
The only reason I gave this a 9 rather than a 10 was that it felt like it was missing *something*, perhaps a bit more discoveries or one or more unlockables wouldn't tipped the balance. VERY highly recommended.