@Dyrian I agree. Having those non-shootable coloured balls on the screen is a bit unfair. But I can see why it would be used in the Challange mode, as it does pressure the player to try and get them to 'drop' off the screen. That was my priority when I played in that mode.
Other than slapping on details into the picture, adding further editing options such as rotating, flipping and resizing for the decorations would be nice?