Samus inside a pinball table sounds weird. But yes, it works pretty fine.
The Bad: The game is short and it ends quickly; bumping the table through the touch screen doesn't work that well.
Nintendo has picked Samus to star the very first pinball game for the DS and even though that sounds weird at first it ended as a really great game that can become a reference for the next dual-screen pinball games yet to come.
The main tables (Tallon Overworld and Pirate Frigate) have an excellent traditional design, emulating real tables; all the other tables take some kind of advantage of good ideas from pinball games that had bosses to defeat, and everything here works pretty fine. Add some great sound effects (including voice acting), beautiful coloring and light/shadow management, the rumble pak working well (for free) and the result is an enjoyable pinball game--and it would still be even if it wasn't a Metroid game.
But it is a Metroid game! And that's the big deal. It gets really interesting when you see that two different universes were merged without any harm to the playability; on the contrary, it's good to listen to that classic melody when you get a new item, or hearing the terrifying music in the Artifact Temple battle, or placing bombs while you're in morphing ball state (which happens most of the time but you can also stand up to shoot some metroids away in some specific situations).
The game doesn't hit the jackpot hard just because of two things: 1) it's really short; and 2) bumping the table through the touch screen is worthless. But after all it's a great work with its objectives achieved.
(It's time to surpass the fever about using each and every DS feature in any game. We already know it all by heart, and it's amazing; when used wisely.)