Actually a pretty good horizontal shmup and kind of reminded me of some of the quirkier amiga ones (not quite as groundbreaking as say apidya but not much will be).
Health bar based (generous but if you lack health it is because you screwed up).
You control with the dpad (ship) and touchscreen (shooting which autofires on touch) which I am prepared to be called on but might be unique in DS shmups. It works well actually so [insert jab at kid icarus].
Largely against enemies although aspects of "missle hell" appear. Enemies are pattern based but enough of them with fairly long cycles and reset options that it feels like actual AI- if you have done medusa heads on hard in Castlevania it is the same idea.
You can upgrade your ship in mission mode (you start of pretty slow so I would invest your first money into a speed upgrade) with a fair amount of options actually so some options for different play styles might arise.
Difficulty.... I doubt we will see any wishing to claim a mastery of it but I have met many turned off by touhou and Cave in recent years and my amiga comment was not out of place either as it is very much a western style shmup.
Art design... you know what I can get behind this actually. The UI is pretty nice as well (moveable transparent overlays in menus- who does that on the DS?).
Very short version- this is one of those shovelware titles that isn't and at 16 megs it is sure thing.