I'll have to second the word of fellow last reviewer. It was quite disappointing indeed. This game really doesn't live up to the original, though I don't think there is need to really start pulling more stars than needed - Everything was still good, just not as good as the first + in a minute, and certainly quite below what we expected from it :( That's 1 star down.
Another half star plucked due to the overall lack of challenge. Just a tip: Don't call it a "challenge mode" if you can die indefinitely, revive without penalty (other than score) on the same screen AND keep items (and enemies dead) on respawn, especially if there is no boss in the whole game. It's really misleading.
That sums up to 3.5 which is kind of nice, considering we did already start with 5 stars due to the great overall quality of the game, especially effects (graphic and sound). Had a good experience, not as good as anticipated.