Much much better than the first game, there is so much to see and do on this one and there's not crappy DS features shoed in for the sake of it. Wasn't into the first, it was way too generic, and though its nothing new the second one is more interesting. Never thought that out of the other big games, that this would be the one I'd play and enjoy more but then I never had high hopes for it.
Best scrolling shooter on the DS, but the best shooter remains Geometry Wars, perhaps until Bangai-O Spirits.