Bangai-O Spirits has a lot going for it. It's obviously aimed squarely at the hardcore DS gamer and while the intense action and high difficulty will probably turn off the casual crowd, it's a solid shooter for anyone who's looking for a challenge.
Pros: Addictive gameplay; great retro feel; all the user created content is sharable.
Cons: Graphical slowdown; very uneven difficulty; too dependent on trial and error.